i***@hotmail.com
2003-12-19 20:00:51 UTC
Different Types of Digital Trunking/Modulation
Project 25 / APCO-25
Project 25 uses the IMBE Vocoder. IMBE stands for Improved Multi-Band
Excitation, and was developed by DVSI Inc. Numerous vendors have
produced Project-25 capable subscriber equipment, including Motorola,
EF Johnson, Uniden, Racal, and others. There are conventional voice
solutions as well as trunking solutions available for this digital
voice solution.
Currently, there are two trunking solutions available that use the
Project-25 vocoder:
Motorola ASTRO IMBE - This is Motorola's APCO-25 compliant digital
solution, and is also called the "ASTRO Digital CAI (Common Air
Interface) Option". This is a proprietary trunking solution that
uses the Project-25 vocoder as it's digital voice solution on top of a
standard Motorola Type II Smartzone system. Some agencies using
Motorola ASTRO APCO-25 IMBE systems include The City of Baltimore,
Jefferson Parrish LA, The Metro Washington Airports Authority, Fairfax
County VA, and Sarasota County FL.
The Motorola ASTRO IMBE solution uses the Motorola Type II 3.6 Kb
Smartzone control channel.
The Motorola ASTRO IMBE solution can allow both analog and Project-25
digital radios to operate on the same network
Project 25 Digital Trunking - This is the Project 25 Digital trunking
solution that is vendor independent and designed around the Project-25
Digital Trunking standards. The State of Michigan and the State of
Colorado are two of the few systems that uses this format. Very few
Project-25 Digital trunking solutions have been deployed at this time.
Project 25 Trunking uses a 9.6 Kb control channel.
All radios on a Project-25 Digital trunking system must use digital
voice - no analog trunking capability is provided.
Uniden has recently developed two scanners with an add-in card to
monitor APCO-25 / Project-25 systems. Motorola ASTRO IMBE systems can
be monitored and tracked with the newest generation of Uniden Digital
Trunktrackers. Project-25 Trunking systems using the 9.6 Kb control
channel can only be monitored in conventional mode, they cannot be
tracked using a trunktracker scanner.
Motorola ASTRO VSELP
VSELP stands for Vector Sum Excited Linear Prediction. This is
Motorola's original 1st generation "ASTRO" digital product. Some
agencies that are currently using the VSELP Vocoder include The City
of Cleveland ASTRO system and the City of Memphis ASTRO Public Safety
System. Note that the VSELP implementation of ASTRO is not APCO-25
compliant.
Motorola VSELP systems exclusively use the standard Type II Motorola
3.6Kb control channel.
Fortunately, these systems are being phased out in favor of APCO-25 /
Project-25 systems.
MA/Com Ericsson EDACS ProVoice
This is MA/Com / Ericsson's implementation of IMBE Digital modulation.
It is NOT APCO-25 compliant, but does use the same IMBE vocoder
developed by DVSI Inc. The only difference from the APCO-25 standard
is how error correction and modulation is provided to transmit the
data. San Antonio TX, The State of Florida, and St Tammany Parish are
using ProVoice EDACS solutions.
EDACS ProVoice systems use the MA/Com / GE EDACS Control Channel.
There is not a scanner available today that can monitor EDACS ProVoice
Digital voice.
MA/Com Ericsson EDACS AEGIS
This is MA/Com / Ericsson's implementation of IMBE Digital modulation.
Very few agencies today are using AEGIS Digital Voice solutions,
since they are 1st generation digital voice solutions and considered
dated.
EDACS AEGIS systems use the MA/Com / GE EDACS Control Channel.
There is not a scanner available today that can monitor EDACS AEGIS
Digital voice.
MA/Com Ericsson OpenSky©
This is MA/Com / Ericsson's implementation of AMBE Digital modulation
over a TDMA Channel Format/Slot. AMBE is another vocoder developed
by DVSI Inc. The State of Pennsylvania is deploying an OpenSky
solution. Operation is very similar to Nextel TDMA Digital Voice
systems.
OpenSky systems do not use a control channel.
There is not a scanner available today that can monitor OpenSky AMBE
Digital voice.
iDEN© (Integrated Digital Enhanced Network)
iDEN is a Motorola developed high-capacity digital trunking solution
in use primarily for SMR's and Business Applications. Nextel is
developed and based on the iDEN network infrastructure. iDEN is
reported to use the VSELP vocoder, over a 6:1 TDMA Channel.
There is not a scanner available today that can monitor iDEN Digital
Voice Systems.
Tetrapol
Tetrapol is an open digital voice standard in use primarily in Europe
and overseas from the United States. It uses a 12.5 kHz FDMA GMSK
channel.
There is not a scanner available today that can monitor Tetrapol
Digital Voice Systems.
Tetra Digital Voice Standard
Tetra is an open digital voice standard developed by the European
Telecom Standards Institute (ETSI) and is in use primarily in Europe
and overseas from the United States. It uses a 4-Slot TDMA channel.
Please see the Tetra Digital Information Page for more information on
Tetra systems.
Tetra systems use the Tetra Control Channel.
There is not a scanner available today that can monitor Tetra Digital
Voice Systems.
Additional APCO-25 / Project 25 Information
APCO-25 is a project headed by The Association of Public Safety
Communications Officials to create a common architecture for two-way
radio digital technology. APCO-25 defines the standards that digital
two-way radio communications networks will use so that
interoperability is a success and so effective bandwidth utilization
is maintained. It also defines the technical standards such as
Vocoder, bandwidth, signaling, and other features. The PRIMARY goal of
APCO-25 digital modulation is to reduce bandwidth requirements for
public safety communications, NOT to prevent scanner listeners from
hearing communications.
APCO-25 is an open standard, thus there is a lot of information
available regarding it.
APCO-25 Homepages
Project 25 Interest Groups Homepage - General information on the
Project 25 User Group Homepage. Downloadable PDF's and more.
Project 25 Overview - PDF Document with general Project 25
information.
Project 25 Discussion List -Yahoogroups mailing list dedicated to
project-25 information.
US Army Nationwide Digital Trunked Radio - The US Army is deploying
digital trunking systems for numerous military and federal agencies
around the United States. Here you can find detailed information about
there project, their current users, and status updates regarding the
BRS.
The APCO International Web Site - This page is homepage for the
Association of Public Safety Communications Officials. They are the
group that defines standards for Public Safety communications in the
United States
The APCO Project 25 Homepage - Here you can find white papers and
technical documents regarding the APCO-25 Digital public safety
project - on the APCO International Web Site
Users Accelerate Move To Project 25 Systems, Technology - An APCO
bulletin posted on the Motorola Web site. This outlines how many large
Public Safety agencies across the U.S. have chosen APCO-25 compliant
digital system for Public Safety communications. Gives examples of
which agencies have made the switch, and which agencies are about to.
APCO-25 Vendors and Equipment information
Motorola APCO Project 25 Homepage - Detailed information on Motorola's
Project 25 compatible solution called ASTRO.
Motorola ASTRO Radios - Pictures and description of ASTRO digital
mobiles and portables at Motorola's Web Site.
APCO-25 Decoding, Scanners, and other technical information
Digital Voice Systems Inc. Homepage - DVSI produces many of the
microprocessors, software, and vocoders used for public safety digital
voice systems. Lots of data sheets and information on this web site.
Motorola Encryption techniques - DVP, DES, Securenet, ASTRO, and
Fascinator are all discussed here.
http://www.p25.com/ - IFR's homepage designed to communicate the
latest information regarding APCO-25 Digital Testing technologies.
Much of the information here centers around the IFR 2975 Project 25
Service Monitor. Lots of good reference information here.
Interesting post - posted to Usenet regarding decoding APCO-25 digital
signals. This was written by a college student who was developing an
APCO-25 digital decoder as a class project. Although we never actually
saw anything come out of this, the information posted is very useful
non-the-less. Interesting Reading!
Digital Source Coding of Speech Signals - Great information on
vocoders, and the IMBE Vocoder standard developed by DVSI.
IMBE and AMBE Speech Compression - [PDF] - Article describing the
scientific theory behind the IMBE and AMBE Speech Compression
Vocoders. From the Engineering Electronic Times.
------------
Different Types and Flavors of Motorola Systems
Types of Motorola Trunked Systems
Type I Systems - Motorola Type I Systems refer to the original
Motorola systems that were based on Fleets and Subfleets. Each system
had a certain number of Fleets assigned, and then each Fleet had a
certain number of Subfleets and radio ids. The distribution of Fleets
and Subfleets on a Type I system is determined by the system Fleetmap.
Motorola Type I systems are not scalable because they limit the amount
of IDs any fleet or subfleet can support.
Type II Systems - Motorola Type II systems refer to the the second
generation Motorola Trunking systems that replaced Fleets and
Subfleets with the concept of talkgroups and individual radio IDs.
There are no dependencies on Fleetmaps, therefore there are no
limitations to how many radio ids that can participate on a talkgroup.
This allows for greater flexibility for the agency.
Hybrid Systems - A Motorola Hybrid system has "blocks" of the system
that are Type I Fleets/Subfleets and Type II talkgroups. All radios
may be Type II, or the Type I radios might be used exclusively in
subfleets while the Type IIs are used exclusively in talkgroups.
Type IIi Systems - Motorola Type IIi Hybrid is a system that has Type
I fleets and subfleets, and has Type II radios that are able to use
those Type I fleet/subfleets. The common reason that an agency sets up
a Type IIi Hybrid system is because they have newer Type II radios
that they want to interoperate with older Type I radios, without
having to create new Type II talkgroups.
Type IIi Hybrid Systems - A mixture of Hybrid and IIi.
Flavors of Motorola Trunked Systems
Type I (Privacy Plus) - The term "Privacy Plus" refers to a Type I
system. Privacy Plus systems are normally older Public Safety systems
and SMRs (Specialized Mobile Radio - Businesses who rent out space on
trunking systems)
Type II (Smartnet ) - The term Smartnet refers to a set of features
made available for Public Safety users. This includes better security,
emergency signaling, dynamic regrouping, remote radio monitoring, and
other features. The following is true of a Type II Smartnet system.
- Up to 28 system channels
- Up to 65535 unique radio ids
- Up to 4000 talkgroups
- APCO 16 Compliant
SmartZone - SmartZone systems are Smartnet Type II systems that are
networked together via Microwave or Land-line to provide multi-site
wide area communications. Radios affiliate with a particular site, and
affiliate with a talkgroup which allows the radio to talk on that
talkgroup to other radios on other sites. Many large public safety and
state agencies use SmartZone system for wide area communications. The
following are the characteristics of a Motorola SmartZone system:
- Up to 28 channels per site
- Up to 65535 unique radio ids
- Up to 48 Sites
- Analog and/or Digital voice
- APCO 16 Compliant
Monitoring a SmartZone system with a Trunktracker is the same process
as monitoring any other Smartnet Type II system, except that you can
only monitor one site at a time. For you to monitor a specific
talkgroup on a SmartZone site, someone's radio must be affiliated to
that specific talkgroup. Therefore, if you are monitoring talkgroup
"POLICE-NORTH" on a site where no radios have that talkgroup
affiliated, then you will not hear any communications on that
talkgroup until a radio affiliates to that talkgroup.
SmartZone OmniLink - SmartZone OmniLink provides a broad range of
robust system features and utilizes a distributed call processing
architecture which links up to four multi-site SmartZone™
systems together into one seamless network, supporting up to 192
sites. Typical users of SmartZone OmniLink systems include
organizations who have vast geographic requirements -- such as
Electric and Gas Companies, and extremely Large Public Safety
agencies.
Simulcast - The term simulcast refers to the process of setting up
multiple repeaters to transmit exactly the same communications on the
same frequency. Many agencies setup Simulcast systems to increase
coverage of their single site Motorola system. 1 Site
Controller....multiple transmitters. Cells within multi-site
SmartZone systems can also be setup as simulcast.
ASTRO - ASTRO is the trademark name for Motorola's Digital
Communications Solution. The original Motorola ASTRO implementation
uses the standard SmartZone 3600 baud data channel, and the digital
voice solution is based on the Motorola proprietary VSELP vocoder. For
more information, see the APCO-25 and Digital Trunking Information
Page.
ASTRO CAI - Motorola's APCO-25 compatible Digital Trunking Solution.
This implementation uses the standard SmartZone 3600 baud data
channel, and the digital voice solution is based on the APCO-25 IMBE
vocoder. For more information, see the APCO-25 and Digital Trunking
Information Page.
ASTRO-25 - Motorola's implementation of the Project 25 Digital
Trunking standard, which uses the TIA 9600 baud control channel. For
more information, see the APCO-25 and Digital Trunking Information
Page.
Motorola Trunked Infrastructure Versions
Version Description
2.7 Analog/Securenet SmartZone, adds VOC, ACC and other new
infrastructure features.
2.0.3 Astro/Analog/Securenet VSELP SmartZone
3.0 3600 Astro/analog IMBE SmartZone
3.5 3600 Omnilink (multiple zone support)
4.1 Latest 3600 Omnilink release (replaces OL 3.5. product lifecycle
replacements and updates for several products, including 6809->MTC3600
controllers)
5.0 First P25 9600 infrastructure release, 800 only
5.1 Adds Simulcast and telephone interconnect to 5.0, 800 only
6.0 Adds IP transport of audio on network to 5.1, lifecycle updates
and replacements for several products including, Intellisite repeaters
replace Intellirepeaters for new installations. MGEG replaces DIU for
console vocoder
6.1 Adds (non-simulcast) VHF/UHF P25 trunking to 6.0. Encrypted MGEG.
XTS-2500, XTS-5000 subscribers.
6.2 Adds improved (APCO "explicit mode") support for VHF/UHF P25
trunking, 700 MHz
6.3 P25 Simulcast/voting supported in VHF/UHF/700/800 , P25 trunked
user data
notes 3.X and 4.X are APCO common air interface (CAI) compliant.
5.X and 6.X are compliant with both APCO CAI and APCO trunking
standards.
Motorola Systems Technical Notes
Converting Motorola Talkgroups
Type II talkgroup IDs come in three flavors:
Uniden Trunktracker format such as 41072.
ID Range: (0 - 65504)
Motorola 3 digit Hex variety such as A07.
ID Range: (000 - FFE)
Motorola 6 digit decimal variety such as 802567.
ID Range: (800000 - 804094)
In the following formulas, M3 represents a Motorola 3 digit Hex format
value, M6 represents a Motorola 6 digit decimal format value, and U
represents a Uniden format value.
The notation Dec_to_Hex(X) means convert X to its Hex equivalent.
The notation Hex_to_Dec(X) means convert X to its Decimal equivalent.
To convert Use this Formula
---------- -----------------
M6 to U (M6 - 800000)*16 = U
M6 to M3 Dec_to_Hex(M6 - 800000) = M3
M3 to U Hex_to_Dec(M3)*16 = U
M3 to M6 Hex_to_Dec(M3) + 800000 = M6
U to M3 Dec_to_Hex(U/16) = M3
U to M6 U/16 + 800000 = M6
Examples:
Convert the M6 format ID, 802617 to U format:
(802617 - 800000)*16 = 41872
Convert the M6 format ID, 802617 to M3 format:
Dec_to_Hex(802617 - 800000) => Dec_to_Hex(2617) = A39
Convert the M3 format ID, A39 to U format:
Hex_to_Dec(A39)*16 => 2617*16 = 41872
Convert the M3 format ID, A39 to M6 format:
Hex_to_Dec(A39) + 800000 => 2617 + 800000 = 802617
Convert the U format ID, 41872 to M3 format:
Dec_to_Hex(41872/16) => Dec_to_Hex(2617) = A39
Convert the U format ID, 41872 to M6 format:
41872/16 + 800000 = 802617
Type II System Special Status Bits
Type II Smartnet systems use these status bits for special
transmissions such as Emergency, Patches, DES/DVP scrambled
transmissions, and Multiselects on Motorola Trunking systems. Motorola
Trunking radios directly interpret them for their special functions,
thus no difference is noticed by the person with the radio. The
Trunktracker scanners however interpret these special talkgroup status
bits as different talkgroups entirely. Below is the conversion chart
for these special status bits.
TTID + # Usage
ID+0 Normal Talkgroup
ID+1 All Talkgroup
ID+2 Emergency
ID+3 talkgroup patch to another
ID+4 Emergency Patch
ID+5 Emergency multi-group
ID+6 Not assigned
ID+7 Multi-select (initiated by dispatcher)
ID+8 DES Encryption talkgroup
ID+9 DES All Talkgroup
ID+10 DES Emergency
ID+11 DES Talkgroup patch
ID+12 DES Emergency Patch
ID+13 DES Emergency multi-group
ID+14 Not assigned
ID+15 Multi-select DES TG
Therefore, if a user was transmitting a multi-select call on talkgroup
1808, the trunktracker would actually receive those transmissions on
1815. Some common uses of these status bits are as follows:
When a user hits their emergency button, all conversations on the
talkgroup revert to the Emergency status talkgroup (ID+2) until the
dispatch clears the emergency status. Therefore, if someone hit their
emergency button and their radio was on talkgroup 16, all
communications would switch to talkgroup 18.
A lot of Fire and EMS departments dispatch tone-outs an alarms as
Multi-select communications (ID+7). Therefore, if your fire department
dispatch talkgroup is 1616, and they do dispatch tone-outs and alarms
as Multi-selects, then those communications will be on talkgroup 1623.
This can be a problem, because you will miss communications if you
don't have those talkgroups programmed. By setting the Type II block
you are monitoring with a fleetmap of S-1 (Mot Size A), you'll
essentially get Type I subfleets for each Type II talkgroup -
encompassing all of the status bits into one subfleet.
Type I Block Size Codes
These size codes are used for fleet mapping Type I Systems
Motorola A B C D E F G H I J K M O Q
Trunktracker S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 S11 S12 S13 S14
Trunker.exe A B C D E F G H I J K L M N
Size Code Parameters
Motorola TT Trunker.exe Fleets Subfleets Ids
A S1 A 128 4 16
B S2 B 16 8 54
C S3 C 8 8 128
D S4 D 1 16 512
E S5 E 64 4 32
F S6 F 32 8 32
G S7 G 32 4 64
H S8 H 16 4 128
I S9 I 8 4 256
J S10 J 4 8 256
K S11 K 2 16 256
M S12 L 1 16 1024
O S13 M 1 16 2048
Q S14 N 1 16 4096
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EDACS Trunking Information
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EDACS Overview
EDACS was created by General Electric and then further engineered by
Ericsson. The EDACS technology has changed numerous owners and now is
currently owned by M/A Com.
EDACS is a lot similar to Motorola trunking. It provides for the same
features yet has different names for them. Simulcast networks work the
same yet EDACS networks, which are similar to AMSS networks, are all
independent of each other but still interconnected. A radio is
programmed with each system independently and selects each system
based on control channel quality. Rather than have a site number a
system is basically assigned a simple number to differentiate it.
Motorola uses a specific bandplan or a complicated frequency defined
system to assign frequencies. EDACS uses what are called Logical
Channel Numbers [LCN]. Rather than assign a frequency with a specific
identifier, each frequency at a site is assigned a number between 1
through 21. When a channel announcement occurs it contains only the
LCN. With this in mind each radio must be programmed with which
frequency corresponds to which LCN.
Digital communications is also available for EDACS systems and exists
in two different formats, AEGIS and Pro Voice. AEGIS was the first
format introduced and Pro Voice was the last and current format.
Neither one is APCO-25 compliant unlike Motorola’s ASTRO, which
is. Also, neither AEGIS nor Pro-Voice can communicate with each other.
EDACS Whitepaper - (PDF Format) - This is an excellent whitepaper
written by Com-Net Ericsson regarding how EDACS systems work, EDACS
technologies overview, and other technical details of an EDACS
infrastructure.
--------------------------------------------------------------------------------
EDACS Talkgroups Conversions
The Uniden EDACS format: (Agency Fleet Subfleet)
Using this example (586 DECIMAL = 04-092 AFS = 24a HEX):
(1) 586 decimal = 01001001010 binary (talkgroups are 11-bit binary)
(2) Split the binary as follows 0100 | 1001 | 010
(3) Convert each group to decimal 04 09 2
(4) Format as 04-092
The HEX translation would be:
(1) 586 decimal = 01001001010 binary
(2) Split binary as 010 | 0100 | 1010
(3) Convert each group to HEX 2 4 a
(4) Write as 24a
The BC245 can do the DECIMAL/AFS conversion internally, and the
user can choose either mode of entry and display. So it won't
be necessary to do this by hand.
See this link for an Conversion Table to help with these conversions
between AFS, DEC and HEX.
See this link for an Excel Spreadsheet to convert talkgroups for you.
(Thanks to ***@sprynet.com)
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EDACS Fleet mapping
Establishing a fleet map structure dictates the max number of agency
and fleet calls which can be assigned. Within the fleet map structure,
the more agencies that are setup, the more agency calls that can be
assigned. The same is true for fleet calls. To enhance each agencies
flexibility, you can have different fleet and subfleet structures for
each agency to suit specific radio communications requirements
A group call is addresses using a Group ID (GID). The GID is composed
of 11 bits to define a total of 2048 max groups. The fleet map is
structures for each agency to suit their specific requirements.
Maximum of 5 bits to be used for agencies
Minimum of 1 bit to be used for fleets
Minimum of 2 bits to be used for subfleets
Some examples of the possible fleetmaps are shown below (similar to
Motorola Fleetmaps)
Agencies Fleets Subfleets
2 32 32
2 16 64
2 8 128
2 4 256
4 32 16
8 8 32
8 16 16
16 16 8
The most common fleet map used by EDACS systems is 8 (3 bits)
agencies, 16 (4 bits) fleets and 16 (4 bits) subfleets. If we take a
couple of examples of group calls, you can easily see how simple the
fleet structure really is.
Using a 3/4/4 structure, we can now partition the 11 bit Group ID
(GID) as follows:
_ _ _ / _ _ _ / _ _ _ _
Agency Fleet Subfleet
Binary examples are shown below:
Agency 1, Fleet 1, Subfleet 1 (GID 273 Decimal)
0 0 1 / 0 0 0 1 / 0 0 0 1
Agency 1, Fleet 1, Subfleet 15 (GID 287 Decimal)
0 0 1 / 0 0 0 1 / 1 1 1 1
A group call for Agency 1, Fleet 1, Subfleet 0 (GID 272) is a Fleet
group call. All subfleets in Agency 1, Fleet 1 will respond to the
call. A binary representation is as follows:
0 0 1 / 0 0 0 1 / 0 0 0 0
When an EDACS radio sees the fleet call assignment (GID 272), it
immediately associates Subfleet 0 as being a Fleet call for Agency 1,
Fleet 1. If the radio's channel selector is on a subfleet within
Agency 1, Fleet 1, the radio hears the call.
A group call for Agency 1, Fleet 0, Subfleet 0 (GID 256) represents an
Agency Group call. All fleets and subfleets in Agency 1 will respond
to the call. A binary representation is as follows:
0 0 1 / 0 0 0 0 / 0 0 0 0
When the radio sees the Fleet call assignment (GID 256), it will
immediately associate Fleet 0, Subfleet 0 as being an Agency call for
Agency 1. If the radio's channel know is on a subfleet within Agency
1, the radio will automatically hear the call on GID 256.
This type of fleet mapping ensures Agency Fleet calls under failure
mode of operation (such if the Site Controller were to fail)
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EDACS Misc. Information
A detailed list from Ericsson outlining all agencies and users
currently using EDACS systems today. This isn't up to date, but useful
non-the-less
On your various EDACS systems TG in the 07f0-07ff (Hex) are patches,
either TG-TG or otherwise. This appears to be a standard range for
EDACS systems.
GTRAC Homepage - Lots of good information about EDACS systems across
the nation
Using Etrunker to monitor your local EDACS system, then make sure you
read this:
All EDACS systems have 25 real LCN channel frequencies, and then an
additional six 'status' channels that show up under Etrunk. They are
not
actual frequencies, but they indicate a certain status message to the
calling radio. Here is what I have added to all my EDACS system
files.
s DOWNLINK,1a,ffff,0
s RESERVED,1b,ffff,0
s CONVERTc,1c,ffff,0
s QUEUEDid,1d,ffff,0
s SYS-BUSY,1e,ffff,0
s DENIEDid,1f,ffff,0
I'm not too sure about the first two, but CONVERTc is used to tell a
radio
who PTTs while there talkgroup is active, and sends them to listen to
the
talkgroup, giving them an error beep as well. QUEUEDid is where a
calling
radio will be placed if they are waiting for a next available voice
channel
or phone patch, etc. SYS-BUSY, means the system is busy, no channels
available, and somebody is in the Queue. DENIEDid is if that radio ID
is
not allowed on the system for some reason.
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EDACS Equipment Information
MA/COM Wireless Corp Homepage - The homepage for the MA/Com Wireless
Corp, which designs, develops, and implements EDACS systems and
technologies.
Racom Inc. - Distributors of Ericsson EDACS equipment. See this link
to their products and services page which has detailed information on
Ericsson EDACS mobile and portable radios.
Hall Electronics GETECH Page - Lots of detailed information on
progamming Com-Net Ericsson Radio equipment here. Cable pin-outs,
connections, software versions etc can be found at this page for most
of Com-Net Ericsson's radio equipment.
--------------------------------------------------------------------------------
EDACS System Overview
Enhanced Digital Access Communications System (EDACS) is available in
VHF, UHF, 800 and 900 frequency bands and wideband (25 kHz) and
narrowband (12.5 kHz) configurations. This spectrum resource provided
a springboard for the development of trunking systems. Public service
radio manufactures working with Associated Public-Safety
Communications Officers (APCO) developed a requirements document (APCO
16) for trunked radio systems.
EDACS provides coordinated communication between agencies and
integrates all services; Dispatch, Secure Voice, Telephone and Data
within a single common communication system. EDACS systems have a
single control channel communicating between the system and the field
radios. These configurations range from Basic EDACS to EDACS Level 4,
consisting of Voted and Simulcast Systems. An EDACS Multisite Network
links Systems together via a Multisite Controller (MSC) or Integrated
Multisite and Console Controller (IMC).
There are two types of radio channel designations are used in EDACS:
One of them is the Control Channel and the other is the Working
Channel. The Control Channel is used to send digital data between
sites to the radios. This data is continually transmitted to the field
units. The Working Channels sends voice and data over the air.
Control Channel
Used for continuous data (full duplex) Inbound and Outbound 9600/4800
bits per second.
Working Channel
Up to 23 per Site
Voice and Data
Data message 9600/4800 bits per second.
Low Speed Data for updating units: Analog Calls 150 Bits per sec,
Individual and scan group calls
Units will send 75Hz and 150Hz Trunked Unit Transmitting.
Failsoft Trunking
Control Channel GETC must be reset to bring site out of Failsoft
Manual or Remote accomplished.
Failsoft sites can work in Multisite configuration less than .5 second
Channel Access.
If NO Working Channel available the Call goes into Queuing an
available channel.
Data Rate
Wide Band (25/30) kHz: 9600 baud
Narrow Band (12.5) kHz 4800 baud
Data Synchronization
9600 Baud Rate at 0.1 bit (0.01ms)
150 Baud Rate at 0.01 bit (0.06ms)
Audio Equalization
Amplitude of 0.25 dB (300-3000Hz)
Phase of 25 degrees (600-2600 Hz)
Channel Access
Channel Access Time: Less than 500 ms
Timing and Distance Limitations
Max ISI Time: 52 uS (Allowing for 10 uS of Jitter)
Max Site Separation: 7.8 miles (Without Timing Adjustments)
Velocity of Propagation: 3.0 X 10E8 m/s
9600 Baud Period: 104 uS
Path Requirements
Bell Standard T1 or DS1 Grade Circuits Via: Digital Microwave - Fiber
Optic - Phase Stable Analog Multiplex / Microwave
Logical ID
Total Number of Logical Address Schemes: 16,384 (0 to 16,383)
Logical ID uses 14 bits
Used for System Validation
LID 0: Test Unit when making Test Calls
LID < 64 for Host Computers or Mainframe
LID > 100 for Consoles
Group ID
Total Number of Group Address Scheme: 0 to 2048
Physical ID
Each Radio has a Physical ID
20 bits Physical ID
1,048,576 possibilities
ESN
Simulcast
Simultaneous Broadcast by two or more transmitters located at
different sites operating on the same RF Frequency. A Simulcast
trunked system requires the same number of channels with a common set
of RF Frequencies at each site. For this reason, alignment of
simulcast systems become very important.
Capture
The ability of an FM Discriminator to lock on the incoming signal: RF
Level 1 > RF Level 2 by 12
----------
Overview
LTR stands for "Logical Trunked Radio." LTR systems typically do not
have a dedicated control channel. Each repeater has its own
controller, and all of these controllers are synchronized together.
Even though each controller monitors it's own channel, one of the
channel controllers is assigned to be a master that all controllers
report to. Each of these controllers sends out a data burst
approximately every 10 seconds so that the subscriber units know that
the system is there.
This is how you can tell that the system you are listening to is using
LTR. On every channel in the system you will hear this data burst, to
a scanner user it will sound like a short blip of static like someone
keyed up and unkeyed a radio within about 500 msec. This data burst
is not sent at the same time by all the channels, but happen randomly
throughout all the system channels.
There are two flavors of LTR systems available today:
LTR Regular Systems - typically designed for SMR type operations,
business etc
LTR MultiNet Systems - EFJohnson's Multi-Net II system offers a full
set of features for the public safety market. These features include
the following: an emergency system access switch, the ability to set
priority levels, priority queuing, and the ability to operate in the
conventional mode if the need arises. All EFJohnson Multi-Net II
systems follow the technical guidelines documented in the APCO 16
standard
LTR Talkgroups
LTR Talkgroups are in the following format
105001
Area Home Group
1 05 001
Links to LTR Information
An Introduction to LTR Trunking concepts - an excellent technical
overview on how LTR systems work.
Misc
An LTR Data Slicer Circuit. This could be used to develop a LTR
decoder in the future. Also in JPG Format here.
The LCN assignment for a 5 channel system is usually 1 5 9 13 17 for
trunktracking scanners. This is especially important for the new
BC-780XLT Scanner.
-----------
TETRA Trunking Information
--------------------------------------------------------------------------------
Overview
TETRA is the new standard for digital trunked radio systems, that is
changing the nature of the Professional Mobile Radio business. The
standard is defined by ETSI to meet the needs of the most demanding
Professional Mobile Radio users in their dynamically evolving
environment. TETRA has already captured global attention, following
the in footsteps of the GSM standard.
TETRA Facts and Overview - Brief overview and history of the Tetra
Digital Trunked Radio Standard
Links to TETRA Information
The TETRA MOU Homepage - this is the web site for the TETRA MOU
(Memorandum of Understanding) which is the organization responsible
for developing and publishing the TETRA Digital Trunked Radio
Standard.
Motorola's TETRA Homepage - lots of information here regarding
Motorola's entry into the TETRA market, news, information, and product
descriptions.
ETSI Telecom Standards - TETRA Information and technical documentation
on the ETSI Standards Website.
Tetra Digital Standard Information - Excellent web site run by Nokia
which outlines the Tetra standard and its uses for public safety and
commercial environments.
http://thorcom.co.uk/products/mcu500/index.html
http://thorcom.co.uk/products/mnotes/index.html
http://www.rsbick.com/
http://www.police.gov.je/tetra.html
--------------------------------------------------------------------------------
MPT-1327 Overview
MPT 1327 is a industry standard for trunked radio communications
networks. It was developed in 1988 by the British Department of Trade
and Industry (DTI), and is primarily used in the UK, Europe, South
Africa, and Australia.
Systems based on MPT 1327 generally consist of several radio channels.
At least one of these channels is defined as the CC (control channel)
and all other channels are TCs (traffic channels). Data messages
between mobiles and the network are exchanged on the control channel
at 1200 bit/s. Each subscriber in an MPT-1327 trunked radio network
has a unique call number. It consists of a prefix (3 digits), the
fleet number (4 digits) and the subscriber’s call number within
the fleet (2 or 3 digits). After it has been entered the call number
will be converted in the mobile to a 20 bit address.
For the duration of his call a subscriber is exclusively allocated a
traffic channel from the available trunk.
The different types of communications on an MPT-1327 network and their
definitions:
Traffic types:
Mobile-mobile in a cell
Mobile-mobile in different cells
Mobile-line access unit via landline or radio
Mobile-dispatcher station via landline or radio
Mobile-PABX, Mobile-PSTN
Data Communication:
Status messages on the CC (5 bit data length)
Short data messages on the CC (186 bit data length)
Transparent data transmission on the TC (data communication).
Calls:
Point to point connections
Group calls with talk entitlement
Group calls without talk entitlement
Additional MPT-1327 Information on the web
MPT-1327 System Description - Detailed information on MPT-1327 systems
at this link
MPT-1327 and TETRA Trunked Radio Systems Info - Information can be
found here for these two type of trunking protocols (used mainly in
Europe)
MPT-1327 Decoding and Tracking
For MPT-1327/1343 Systems, there is an excellent decoding and
monitoring kit available using the FTrunk application - see the
following link for more details:
http://www.tbsa.com.au/trunk.html
The WinRadio suite of digital decoding applications also supports the
MPT-1327 protocol. Check out the following link for more information
on the WinRadio digital decoding suite of products.
http://www.winradio.com/home/trunking.htm
Project 25 / APCO-25
Project 25 uses the IMBE Vocoder. IMBE stands for Improved Multi-Band
Excitation, and was developed by DVSI Inc. Numerous vendors have
produced Project-25 capable subscriber equipment, including Motorola,
EF Johnson, Uniden, Racal, and others. There are conventional voice
solutions as well as trunking solutions available for this digital
voice solution.
Currently, there are two trunking solutions available that use the
Project-25 vocoder:
Motorola ASTRO IMBE - This is Motorola's APCO-25 compliant digital
solution, and is also called the "ASTRO Digital CAI (Common Air
Interface) Option". This is a proprietary trunking solution that
uses the Project-25 vocoder as it's digital voice solution on top of a
standard Motorola Type II Smartzone system. Some agencies using
Motorola ASTRO APCO-25 IMBE systems include The City of Baltimore,
Jefferson Parrish LA, The Metro Washington Airports Authority, Fairfax
County VA, and Sarasota County FL.
The Motorola ASTRO IMBE solution uses the Motorola Type II 3.6 Kb
Smartzone control channel.
The Motorola ASTRO IMBE solution can allow both analog and Project-25
digital radios to operate on the same network
Project 25 Digital Trunking - This is the Project 25 Digital trunking
solution that is vendor independent and designed around the Project-25
Digital Trunking standards. The State of Michigan and the State of
Colorado are two of the few systems that uses this format. Very few
Project-25 Digital trunking solutions have been deployed at this time.
Project 25 Trunking uses a 9.6 Kb control channel.
All radios on a Project-25 Digital trunking system must use digital
voice - no analog trunking capability is provided.
Uniden has recently developed two scanners with an add-in card to
monitor APCO-25 / Project-25 systems. Motorola ASTRO IMBE systems can
be monitored and tracked with the newest generation of Uniden Digital
Trunktrackers. Project-25 Trunking systems using the 9.6 Kb control
channel can only be monitored in conventional mode, they cannot be
tracked using a trunktracker scanner.
Motorola ASTRO VSELP
VSELP stands for Vector Sum Excited Linear Prediction. This is
Motorola's original 1st generation "ASTRO" digital product. Some
agencies that are currently using the VSELP Vocoder include The City
of Cleveland ASTRO system and the City of Memphis ASTRO Public Safety
System. Note that the VSELP implementation of ASTRO is not APCO-25
compliant.
Motorola VSELP systems exclusively use the standard Type II Motorola
3.6Kb control channel.
Fortunately, these systems are being phased out in favor of APCO-25 /
Project-25 systems.
MA/Com Ericsson EDACS ProVoice
This is MA/Com / Ericsson's implementation of IMBE Digital modulation.
It is NOT APCO-25 compliant, but does use the same IMBE vocoder
developed by DVSI Inc. The only difference from the APCO-25 standard
is how error correction and modulation is provided to transmit the
data. San Antonio TX, The State of Florida, and St Tammany Parish are
using ProVoice EDACS solutions.
EDACS ProVoice systems use the MA/Com / GE EDACS Control Channel.
There is not a scanner available today that can monitor EDACS ProVoice
Digital voice.
MA/Com Ericsson EDACS AEGIS
This is MA/Com / Ericsson's implementation of IMBE Digital modulation.
Very few agencies today are using AEGIS Digital Voice solutions,
since they are 1st generation digital voice solutions and considered
dated.
EDACS AEGIS systems use the MA/Com / GE EDACS Control Channel.
There is not a scanner available today that can monitor EDACS AEGIS
Digital voice.
MA/Com Ericsson OpenSky©
This is MA/Com / Ericsson's implementation of AMBE Digital modulation
over a TDMA Channel Format/Slot. AMBE is another vocoder developed
by DVSI Inc. The State of Pennsylvania is deploying an OpenSky
solution. Operation is very similar to Nextel TDMA Digital Voice
systems.
OpenSky systems do not use a control channel.
There is not a scanner available today that can monitor OpenSky AMBE
Digital voice.
iDEN© (Integrated Digital Enhanced Network)
iDEN is a Motorola developed high-capacity digital trunking solution
in use primarily for SMR's and Business Applications. Nextel is
developed and based on the iDEN network infrastructure. iDEN is
reported to use the VSELP vocoder, over a 6:1 TDMA Channel.
There is not a scanner available today that can monitor iDEN Digital
Voice Systems.
Tetrapol
Tetrapol is an open digital voice standard in use primarily in Europe
and overseas from the United States. It uses a 12.5 kHz FDMA GMSK
channel.
There is not a scanner available today that can monitor Tetrapol
Digital Voice Systems.
Tetra Digital Voice Standard
Tetra is an open digital voice standard developed by the European
Telecom Standards Institute (ETSI) and is in use primarily in Europe
and overseas from the United States. It uses a 4-Slot TDMA channel.
Please see the Tetra Digital Information Page for more information on
Tetra systems.
Tetra systems use the Tetra Control Channel.
There is not a scanner available today that can monitor Tetra Digital
Voice Systems.
Additional APCO-25 / Project 25 Information
APCO-25 is a project headed by The Association of Public Safety
Communications Officials to create a common architecture for two-way
radio digital technology. APCO-25 defines the standards that digital
two-way radio communications networks will use so that
interoperability is a success and so effective bandwidth utilization
is maintained. It also defines the technical standards such as
Vocoder, bandwidth, signaling, and other features. The PRIMARY goal of
APCO-25 digital modulation is to reduce bandwidth requirements for
public safety communications, NOT to prevent scanner listeners from
hearing communications.
APCO-25 is an open standard, thus there is a lot of information
available regarding it.
APCO-25 Homepages
Project 25 Interest Groups Homepage - General information on the
Project 25 User Group Homepage. Downloadable PDF's and more.
Project 25 Overview - PDF Document with general Project 25
information.
Project 25 Discussion List -Yahoogroups mailing list dedicated to
project-25 information.
US Army Nationwide Digital Trunked Radio - The US Army is deploying
digital trunking systems for numerous military and federal agencies
around the United States. Here you can find detailed information about
there project, their current users, and status updates regarding the
BRS.
The APCO International Web Site - This page is homepage for the
Association of Public Safety Communications Officials. They are the
group that defines standards for Public Safety communications in the
United States
The APCO Project 25 Homepage - Here you can find white papers and
technical documents regarding the APCO-25 Digital public safety
project - on the APCO International Web Site
Users Accelerate Move To Project 25 Systems, Technology - An APCO
bulletin posted on the Motorola Web site. This outlines how many large
Public Safety agencies across the U.S. have chosen APCO-25 compliant
digital system for Public Safety communications. Gives examples of
which agencies have made the switch, and which agencies are about to.
APCO-25 Vendors and Equipment information
Motorola APCO Project 25 Homepage - Detailed information on Motorola's
Project 25 compatible solution called ASTRO.
Motorola ASTRO Radios - Pictures and description of ASTRO digital
mobiles and portables at Motorola's Web Site.
APCO-25 Decoding, Scanners, and other technical information
Digital Voice Systems Inc. Homepage - DVSI produces many of the
microprocessors, software, and vocoders used for public safety digital
voice systems. Lots of data sheets and information on this web site.
Motorola Encryption techniques - DVP, DES, Securenet, ASTRO, and
Fascinator are all discussed here.
http://www.p25.com/ - IFR's homepage designed to communicate the
latest information regarding APCO-25 Digital Testing technologies.
Much of the information here centers around the IFR 2975 Project 25
Service Monitor. Lots of good reference information here.
Interesting post - posted to Usenet regarding decoding APCO-25 digital
signals. This was written by a college student who was developing an
APCO-25 digital decoder as a class project. Although we never actually
saw anything come out of this, the information posted is very useful
non-the-less. Interesting Reading!
Digital Source Coding of Speech Signals - Great information on
vocoders, and the IMBE Vocoder standard developed by DVSI.
IMBE and AMBE Speech Compression - [PDF] - Article describing the
scientific theory behind the IMBE and AMBE Speech Compression
Vocoders. From the Engineering Electronic Times.
------------
Different Types and Flavors of Motorola Systems
Types of Motorola Trunked Systems
Type I Systems - Motorola Type I Systems refer to the original
Motorola systems that were based on Fleets and Subfleets. Each system
had a certain number of Fleets assigned, and then each Fleet had a
certain number of Subfleets and radio ids. The distribution of Fleets
and Subfleets on a Type I system is determined by the system Fleetmap.
Motorola Type I systems are not scalable because they limit the amount
of IDs any fleet or subfleet can support.
Type II Systems - Motorola Type II systems refer to the the second
generation Motorola Trunking systems that replaced Fleets and
Subfleets with the concept of talkgroups and individual radio IDs.
There are no dependencies on Fleetmaps, therefore there are no
limitations to how many radio ids that can participate on a talkgroup.
This allows for greater flexibility for the agency.
Hybrid Systems - A Motorola Hybrid system has "blocks" of the system
that are Type I Fleets/Subfleets and Type II talkgroups. All radios
may be Type II, or the Type I radios might be used exclusively in
subfleets while the Type IIs are used exclusively in talkgroups.
Type IIi Systems - Motorola Type IIi Hybrid is a system that has Type
I fleets and subfleets, and has Type II radios that are able to use
those Type I fleet/subfleets. The common reason that an agency sets up
a Type IIi Hybrid system is because they have newer Type II radios
that they want to interoperate with older Type I radios, without
having to create new Type II talkgroups.
Type IIi Hybrid Systems - A mixture of Hybrid and IIi.
Flavors of Motorola Trunked Systems
Type I (Privacy Plus) - The term "Privacy Plus" refers to a Type I
system. Privacy Plus systems are normally older Public Safety systems
and SMRs (Specialized Mobile Radio - Businesses who rent out space on
trunking systems)
Type II (Smartnet ) - The term Smartnet refers to a set of features
made available for Public Safety users. This includes better security,
emergency signaling, dynamic regrouping, remote radio monitoring, and
other features. The following is true of a Type II Smartnet system.
- Up to 28 system channels
- Up to 65535 unique radio ids
- Up to 4000 talkgroups
- APCO 16 Compliant
SmartZone - SmartZone systems are Smartnet Type II systems that are
networked together via Microwave or Land-line to provide multi-site
wide area communications. Radios affiliate with a particular site, and
affiliate with a talkgroup which allows the radio to talk on that
talkgroup to other radios on other sites. Many large public safety and
state agencies use SmartZone system for wide area communications. The
following are the characteristics of a Motorola SmartZone system:
- Up to 28 channels per site
- Up to 65535 unique radio ids
- Up to 48 Sites
- Analog and/or Digital voice
- APCO 16 Compliant
Monitoring a SmartZone system with a Trunktracker is the same process
as monitoring any other Smartnet Type II system, except that you can
only monitor one site at a time. For you to monitor a specific
talkgroup on a SmartZone site, someone's radio must be affiliated to
that specific talkgroup. Therefore, if you are monitoring talkgroup
"POLICE-NORTH" on a site where no radios have that talkgroup
affiliated, then you will not hear any communications on that
talkgroup until a radio affiliates to that talkgroup.
SmartZone OmniLink - SmartZone OmniLink provides a broad range of
robust system features and utilizes a distributed call processing
architecture which links up to four multi-site SmartZone™
systems together into one seamless network, supporting up to 192
sites. Typical users of SmartZone OmniLink systems include
organizations who have vast geographic requirements -- such as
Electric and Gas Companies, and extremely Large Public Safety
agencies.
Simulcast - The term simulcast refers to the process of setting up
multiple repeaters to transmit exactly the same communications on the
same frequency. Many agencies setup Simulcast systems to increase
coverage of their single site Motorola system. 1 Site
Controller....multiple transmitters. Cells within multi-site
SmartZone systems can also be setup as simulcast.
ASTRO - ASTRO is the trademark name for Motorola's Digital
Communications Solution. The original Motorola ASTRO implementation
uses the standard SmartZone 3600 baud data channel, and the digital
voice solution is based on the Motorola proprietary VSELP vocoder. For
more information, see the APCO-25 and Digital Trunking Information
Page.
ASTRO CAI - Motorola's APCO-25 compatible Digital Trunking Solution.
This implementation uses the standard SmartZone 3600 baud data
channel, and the digital voice solution is based on the APCO-25 IMBE
vocoder. For more information, see the APCO-25 and Digital Trunking
Information Page.
ASTRO-25 - Motorola's implementation of the Project 25 Digital
Trunking standard, which uses the TIA 9600 baud control channel. For
more information, see the APCO-25 and Digital Trunking Information
Page.
Motorola Trunked Infrastructure Versions
Version Description
2.7 Analog/Securenet SmartZone, adds VOC, ACC and other new
infrastructure features.
2.0.3 Astro/Analog/Securenet VSELP SmartZone
3.0 3600 Astro/analog IMBE SmartZone
3.5 3600 Omnilink (multiple zone support)
4.1 Latest 3600 Omnilink release (replaces OL 3.5. product lifecycle
replacements and updates for several products, including 6809->MTC3600
controllers)
5.0 First P25 9600 infrastructure release, 800 only
5.1 Adds Simulcast and telephone interconnect to 5.0, 800 only
6.0 Adds IP transport of audio on network to 5.1, lifecycle updates
and replacements for several products including, Intellisite repeaters
replace Intellirepeaters for new installations. MGEG replaces DIU for
console vocoder
6.1 Adds (non-simulcast) VHF/UHF P25 trunking to 6.0. Encrypted MGEG.
XTS-2500, XTS-5000 subscribers.
6.2 Adds improved (APCO "explicit mode") support for VHF/UHF P25
trunking, 700 MHz
6.3 P25 Simulcast/voting supported in VHF/UHF/700/800 , P25 trunked
user data
notes 3.X and 4.X are APCO common air interface (CAI) compliant.
5.X and 6.X are compliant with both APCO CAI and APCO trunking
standards.
Motorola Systems Technical Notes
Converting Motorola Talkgroups
Type II talkgroup IDs come in three flavors:
Uniden Trunktracker format such as 41072.
ID Range: (0 - 65504)
Motorola 3 digit Hex variety such as A07.
ID Range: (000 - FFE)
Motorola 6 digit decimal variety such as 802567.
ID Range: (800000 - 804094)
In the following formulas, M3 represents a Motorola 3 digit Hex format
value, M6 represents a Motorola 6 digit decimal format value, and U
represents a Uniden format value.
The notation Dec_to_Hex(X) means convert X to its Hex equivalent.
The notation Hex_to_Dec(X) means convert X to its Decimal equivalent.
To convert Use this Formula
---------- -----------------
M6 to U (M6 - 800000)*16 = U
M6 to M3 Dec_to_Hex(M6 - 800000) = M3
M3 to U Hex_to_Dec(M3)*16 = U
M3 to M6 Hex_to_Dec(M3) + 800000 = M6
U to M3 Dec_to_Hex(U/16) = M3
U to M6 U/16 + 800000 = M6
Examples:
Convert the M6 format ID, 802617 to U format:
(802617 - 800000)*16 = 41872
Convert the M6 format ID, 802617 to M3 format:
Dec_to_Hex(802617 - 800000) => Dec_to_Hex(2617) = A39
Convert the M3 format ID, A39 to U format:
Hex_to_Dec(A39)*16 => 2617*16 = 41872
Convert the M3 format ID, A39 to M6 format:
Hex_to_Dec(A39) + 800000 => 2617 + 800000 = 802617
Convert the U format ID, 41872 to M3 format:
Dec_to_Hex(41872/16) => Dec_to_Hex(2617) = A39
Convert the U format ID, 41872 to M6 format:
41872/16 + 800000 = 802617
Type II System Special Status Bits
Type II Smartnet systems use these status bits for special
transmissions such as Emergency, Patches, DES/DVP scrambled
transmissions, and Multiselects on Motorola Trunking systems. Motorola
Trunking radios directly interpret them for their special functions,
thus no difference is noticed by the person with the radio. The
Trunktracker scanners however interpret these special talkgroup status
bits as different talkgroups entirely. Below is the conversion chart
for these special status bits.
TTID + # Usage
ID+0 Normal Talkgroup
ID+1 All Talkgroup
ID+2 Emergency
ID+3 talkgroup patch to another
ID+4 Emergency Patch
ID+5 Emergency multi-group
ID+6 Not assigned
ID+7 Multi-select (initiated by dispatcher)
ID+8 DES Encryption talkgroup
ID+9 DES All Talkgroup
ID+10 DES Emergency
ID+11 DES Talkgroup patch
ID+12 DES Emergency Patch
ID+13 DES Emergency multi-group
ID+14 Not assigned
ID+15 Multi-select DES TG
Therefore, if a user was transmitting a multi-select call on talkgroup
1808, the trunktracker would actually receive those transmissions on
1815. Some common uses of these status bits are as follows:
When a user hits their emergency button, all conversations on the
talkgroup revert to the Emergency status talkgroup (ID+2) until the
dispatch clears the emergency status. Therefore, if someone hit their
emergency button and their radio was on talkgroup 16, all
communications would switch to talkgroup 18.
A lot of Fire and EMS departments dispatch tone-outs an alarms as
Multi-select communications (ID+7). Therefore, if your fire department
dispatch talkgroup is 1616, and they do dispatch tone-outs and alarms
as Multi-selects, then those communications will be on talkgroup 1623.
This can be a problem, because you will miss communications if you
don't have those talkgroups programmed. By setting the Type II block
you are monitoring with a fleetmap of S-1 (Mot Size A), you'll
essentially get Type I subfleets for each Type II talkgroup -
encompassing all of the status bits into one subfleet.
Type I Block Size Codes
These size codes are used for fleet mapping Type I Systems
Motorola A B C D E F G H I J K M O Q
Trunktracker S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 S11 S12 S13 S14
Trunker.exe A B C D E F G H I J K L M N
Size Code Parameters
Motorola TT Trunker.exe Fleets Subfleets Ids
A S1 A 128 4 16
B S2 B 16 8 54
C S3 C 8 8 128
D S4 D 1 16 512
E S5 E 64 4 32
F S6 F 32 8 32
G S7 G 32 4 64
H S8 H 16 4 128
I S9 I 8 4 256
J S10 J 4 8 256
K S11 K 2 16 256
M S12 L 1 16 1024
O S13 M 1 16 2048
Q S14 N 1 16 4096
--------------
EDACS Trunking Information
--------------------------------------------------------------------------------
EDACS Overview
EDACS was created by General Electric and then further engineered by
Ericsson. The EDACS technology has changed numerous owners and now is
currently owned by M/A Com.
EDACS is a lot similar to Motorola trunking. It provides for the same
features yet has different names for them. Simulcast networks work the
same yet EDACS networks, which are similar to AMSS networks, are all
independent of each other but still interconnected. A radio is
programmed with each system independently and selects each system
based on control channel quality. Rather than have a site number a
system is basically assigned a simple number to differentiate it.
Motorola uses a specific bandplan or a complicated frequency defined
system to assign frequencies. EDACS uses what are called Logical
Channel Numbers [LCN]. Rather than assign a frequency with a specific
identifier, each frequency at a site is assigned a number between 1
through 21. When a channel announcement occurs it contains only the
LCN. With this in mind each radio must be programmed with which
frequency corresponds to which LCN.
Digital communications is also available for EDACS systems and exists
in two different formats, AEGIS and Pro Voice. AEGIS was the first
format introduced and Pro Voice was the last and current format.
Neither one is APCO-25 compliant unlike Motorola’s ASTRO, which
is. Also, neither AEGIS nor Pro-Voice can communicate with each other.
EDACS Whitepaper - (PDF Format) - This is an excellent whitepaper
written by Com-Net Ericsson regarding how EDACS systems work, EDACS
technologies overview, and other technical details of an EDACS
infrastructure.
--------------------------------------------------------------------------------
EDACS Talkgroups Conversions
The Uniden EDACS format: (Agency Fleet Subfleet)
Using this example (586 DECIMAL = 04-092 AFS = 24a HEX):
(1) 586 decimal = 01001001010 binary (talkgroups are 11-bit binary)
(2) Split the binary as follows 0100 | 1001 | 010
(3) Convert each group to decimal 04 09 2
(4) Format as 04-092
The HEX translation would be:
(1) 586 decimal = 01001001010 binary
(2) Split binary as 010 | 0100 | 1010
(3) Convert each group to HEX 2 4 a
(4) Write as 24a
The BC245 can do the DECIMAL/AFS conversion internally, and the
user can choose either mode of entry and display. So it won't
be necessary to do this by hand.
See this link for an Conversion Table to help with these conversions
between AFS, DEC and HEX.
See this link for an Excel Spreadsheet to convert talkgroups for you.
(Thanks to ***@sprynet.com)
--------------------------------------------------------------------------------
EDACS Fleet mapping
Establishing a fleet map structure dictates the max number of agency
and fleet calls which can be assigned. Within the fleet map structure,
the more agencies that are setup, the more agency calls that can be
assigned. The same is true for fleet calls. To enhance each agencies
flexibility, you can have different fleet and subfleet structures for
each agency to suit specific radio communications requirements
A group call is addresses using a Group ID (GID). The GID is composed
of 11 bits to define a total of 2048 max groups. The fleet map is
structures for each agency to suit their specific requirements.
Maximum of 5 bits to be used for agencies
Minimum of 1 bit to be used for fleets
Minimum of 2 bits to be used for subfleets
Some examples of the possible fleetmaps are shown below (similar to
Motorola Fleetmaps)
Agencies Fleets Subfleets
2 32 32
2 16 64
2 8 128
2 4 256
4 32 16
8 8 32
8 16 16
16 16 8
The most common fleet map used by EDACS systems is 8 (3 bits)
agencies, 16 (4 bits) fleets and 16 (4 bits) subfleets. If we take a
couple of examples of group calls, you can easily see how simple the
fleet structure really is.
Using a 3/4/4 structure, we can now partition the 11 bit Group ID
(GID) as follows:
_ _ _ / _ _ _ / _ _ _ _
Agency Fleet Subfleet
Binary examples are shown below:
Agency 1, Fleet 1, Subfleet 1 (GID 273 Decimal)
0 0 1 / 0 0 0 1 / 0 0 0 1
Agency 1, Fleet 1, Subfleet 15 (GID 287 Decimal)
0 0 1 / 0 0 0 1 / 1 1 1 1
A group call for Agency 1, Fleet 1, Subfleet 0 (GID 272) is a Fleet
group call. All subfleets in Agency 1, Fleet 1 will respond to the
call. A binary representation is as follows:
0 0 1 / 0 0 0 1 / 0 0 0 0
When an EDACS radio sees the fleet call assignment (GID 272), it
immediately associates Subfleet 0 as being a Fleet call for Agency 1,
Fleet 1. If the radio's channel selector is on a subfleet within
Agency 1, Fleet 1, the radio hears the call.
A group call for Agency 1, Fleet 0, Subfleet 0 (GID 256) represents an
Agency Group call. All fleets and subfleets in Agency 1 will respond
to the call. A binary representation is as follows:
0 0 1 / 0 0 0 0 / 0 0 0 0
When the radio sees the Fleet call assignment (GID 256), it will
immediately associate Fleet 0, Subfleet 0 as being an Agency call for
Agency 1. If the radio's channel know is on a subfleet within Agency
1, the radio will automatically hear the call on GID 256.
This type of fleet mapping ensures Agency Fleet calls under failure
mode of operation (such if the Site Controller were to fail)
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EDACS Misc. Information
A detailed list from Ericsson outlining all agencies and users
currently using EDACS systems today. This isn't up to date, but useful
non-the-less
On your various EDACS systems TG in the 07f0-07ff (Hex) are patches,
either TG-TG or otherwise. This appears to be a standard range for
EDACS systems.
GTRAC Homepage - Lots of good information about EDACS systems across
the nation
Using Etrunker to monitor your local EDACS system, then make sure you
read this:
All EDACS systems have 25 real LCN channel frequencies, and then an
additional six 'status' channels that show up under Etrunk. They are
not
actual frequencies, but they indicate a certain status message to the
calling radio. Here is what I have added to all my EDACS system
files.
s DOWNLINK,1a,ffff,0
s RESERVED,1b,ffff,0
s CONVERTc,1c,ffff,0
s QUEUEDid,1d,ffff,0
s SYS-BUSY,1e,ffff,0
s DENIEDid,1f,ffff,0
I'm not too sure about the first two, but CONVERTc is used to tell a
radio
who PTTs while there talkgroup is active, and sends them to listen to
the
talkgroup, giving them an error beep as well. QUEUEDid is where a
calling
radio will be placed if they are waiting for a next available voice
channel
or phone patch, etc. SYS-BUSY, means the system is busy, no channels
available, and somebody is in the Queue. DENIEDid is if that radio ID
is
not allowed on the system for some reason.
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EDACS Equipment Information
MA/COM Wireless Corp Homepage - The homepage for the MA/Com Wireless
Corp, which designs, develops, and implements EDACS systems and
technologies.
Racom Inc. - Distributors of Ericsson EDACS equipment. See this link
to their products and services page which has detailed information on
Ericsson EDACS mobile and portable radios.
Hall Electronics GETECH Page - Lots of detailed information on
progamming Com-Net Ericsson Radio equipment here. Cable pin-outs,
connections, software versions etc can be found at this page for most
of Com-Net Ericsson's radio equipment.
--------------------------------------------------------------------------------
EDACS System Overview
Enhanced Digital Access Communications System (EDACS) is available in
VHF, UHF, 800 and 900 frequency bands and wideband (25 kHz) and
narrowband (12.5 kHz) configurations. This spectrum resource provided
a springboard for the development of trunking systems. Public service
radio manufactures working with Associated Public-Safety
Communications Officers (APCO) developed a requirements document (APCO
16) for trunked radio systems.
EDACS provides coordinated communication between agencies and
integrates all services; Dispatch, Secure Voice, Telephone and Data
within a single common communication system. EDACS systems have a
single control channel communicating between the system and the field
radios. These configurations range from Basic EDACS to EDACS Level 4,
consisting of Voted and Simulcast Systems. An EDACS Multisite Network
links Systems together via a Multisite Controller (MSC) or Integrated
Multisite and Console Controller (IMC).
There are two types of radio channel designations are used in EDACS:
One of them is the Control Channel and the other is the Working
Channel. The Control Channel is used to send digital data between
sites to the radios. This data is continually transmitted to the field
units. The Working Channels sends voice and data over the air.
Control Channel
Used for continuous data (full duplex) Inbound and Outbound 9600/4800
bits per second.
Working Channel
Up to 23 per Site
Voice and Data
Data message 9600/4800 bits per second.
Low Speed Data for updating units: Analog Calls 150 Bits per sec,
Individual and scan group calls
Units will send 75Hz and 150Hz Trunked Unit Transmitting.
Failsoft Trunking
Control Channel GETC must be reset to bring site out of Failsoft
Manual or Remote accomplished.
Failsoft sites can work in Multisite configuration less than .5 second
Channel Access.
If NO Working Channel available the Call goes into Queuing an
available channel.
Data Rate
Wide Band (25/30) kHz: 9600 baud
Narrow Band (12.5) kHz 4800 baud
Data Synchronization
9600 Baud Rate at 0.1 bit (0.01ms)
150 Baud Rate at 0.01 bit (0.06ms)
Audio Equalization
Amplitude of 0.25 dB (300-3000Hz)
Phase of 25 degrees (600-2600 Hz)
Channel Access
Channel Access Time: Less than 500 ms
Timing and Distance Limitations
Max ISI Time: 52 uS (Allowing for 10 uS of Jitter)
Max Site Separation: 7.8 miles (Without Timing Adjustments)
Velocity of Propagation: 3.0 X 10E8 m/s
9600 Baud Period: 104 uS
Path Requirements
Bell Standard T1 or DS1 Grade Circuits Via: Digital Microwave - Fiber
Optic - Phase Stable Analog Multiplex / Microwave
Logical ID
Total Number of Logical Address Schemes: 16,384 (0 to 16,383)
Logical ID uses 14 bits
Used for System Validation
LID 0: Test Unit when making Test Calls
LID < 64 for Host Computers or Mainframe
LID > 100 for Consoles
Group ID
Total Number of Group Address Scheme: 0 to 2048
Physical ID
Each Radio has a Physical ID
20 bits Physical ID
1,048,576 possibilities
ESN
Simulcast
Simultaneous Broadcast by two or more transmitters located at
different sites operating on the same RF Frequency. A Simulcast
trunked system requires the same number of channels with a common set
of RF Frequencies at each site. For this reason, alignment of
simulcast systems become very important.
Capture
The ability of an FM Discriminator to lock on the incoming signal: RF
Level 1 > RF Level 2 by 12
----------
Overview
LTR stands for "Logical Trunked Radio." LTR systems typically do not
have a dedicated control channel. Each repeater has its own
controller, and all of these controllers are synchronized together.
Even though each controller monitors it's own channel, one of the
channel controllers is assigned to be a master that all controllers
report to. Each of these controllers sends out a data burst
approximately every 10 seconds so that the subscriber units know that
the system is there.
This is how you can tell that the system you are listening to is using
LTR. On every channel in the system you will hear this data burst, to
a scanner user it will sound like a short blip of static like someone
keyed up and unkeyed a radio within about 500 msec. This data burst
is not sent at the same time by all the channels, but happen randomly
throughout all the system channels.
There are two flavors of LTR systems available today:
LTR Regular Systems - typically designed for SMR type operations,
business etc
LTR MultiNet Systems - EFJohnson's Multi-Net II system offers a full
set of features for the public safety market. These features include
the following: an emergency system access switch, the ability to set
priority levels, priority queuing, and the ability to operate in the
conventional mode if the need arises. All EFJohnson Multi-Net II
systems follow the technical guidelines documented in the APCO 16
standard
LTR Talkgroups
LTR Talkgroups are in the following format
105001
Area Home Group
1 05 001
Links to LTR Information
An Introduction to LTR Trunking concepts - an excellent technical
overview on how LTR systems work.
Misc
An LTR Data Slicer Circuit. This could be used to develop a LTR
decoder in the future. Also in JPG Format here.
The LCN assignment for a 5 channel system is usually 1 5 9 13 17 for
trunktracking scanners. This is especially important for the new
BC-780XLT Scanner.
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TETRA Trunking Information
--------------------------------------------------------------------------------
Overview
TETRA is the new standard for digital trunked radio systems, that is
changing the nature of the Professional Mobile Radio business. The
standard is defined by ETSI to meet the needs of the most demanding
Professional Mobile Radio users in their dynamically evolving
environment. TETRA has already captured global attention, following
the in footsteps of the GSM standard.
TETRA Facts and Overview - Brief overview and history of the Tetra
Digital Trunked Radio Standard
Links to TETRA Information
The TETRA MOU Homepage - this is the web site for the TETRA MOU
(Memorandum of Understanding) which is the organization responsible
for developing and publishing the TETRA Digital Trunked Radio
Standard.
Motorola's TETRA Homepage - lots of information here regarding
Motorola's entry into the TETRA market, news, information, and product
descriptions.
ETSI Telecom Standards - TETRA Information and technical documentation
on the ETSI Standards Website.
Tetra Digital Standard Information - Excellent web site run by Nokia
which outlines the Tetra standard and its uses for public safety and
commercial environments.
http://thorcom.co.uk/products/mcu500/index.html
http://thorcom.co.uk/products/mnotes/index.html
http://www.rsbick.com/
http://www.police.gov.je/tetra.html
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MPT-1327 Overview
MPT 1327 is a industry standard for trunked radio communications
networks. It was developed in 1988 by the British Department of Trade
and Industry (DTI), and is primarily used in the UK, Europe, South
Africa, and Australia.
Systems based on MPT 1327 generally consist of several radio channels.
At least one of these channels is defined as the CC (control channel)
and all other channels are TCs (traffic channels). Data messages
between mobiles and the network are exchanged on the control channel
at 1200 bit/s. Each subscriber in an MPT-1327 trunked radio network
has a unique call number. It consists of a prefix (3 digits), the
fleet number (4 digits) and the subscriber’s call number within
the fleet (2 or 3 digits). After it has been entered the call number
will be converted in the mobile to a 20 bit address.
For the duration of his call a subscriber is exclusively allocated a
traffic channel from the available trunk.
The different types of communications on an MPT-1327 network and their
definitions:
Traffic types:
Mobile-mobile in a cell
Mobile-mobile in different cells
Mobile-line access unit via landline or radio
Mobile-dispatcher station via landline or radio
Mobile-PABX, Mobile-PSTN
Data Communication:
Status messages on the CC (5 bit data length)
Short data messages on the CC (186 bit data length)
Transparent data transmission on the TC (data communication).
Calls:
Point to point connections
Group calls with talk entitlement
Group calls without talk entitlement
Additional MPT-1327 Information on the web
MPT-1327 System Description - Detailed information on MPT-1327 systems
at this link
MPT-1327 and TETRA Trunked Radio Systems Info - Information can be
found here for these two type of trunking protocols (used mainly in
Europe)
MPT-1327 Decoding and Tracking
For MPT-1327/1343 Systems, there is an excellent decoding and
monitoring kit available using the FTrunk application - see the
following link for more details:
http://www.tbsa.com.au/trunk.html
The WinRadio suite of digital decoding applications also supports the
MPT-1327 protocol. Check out the following link for more information
on the WinRadio digital decoding suite of products.
http://www.winradio.com/home/trunking.htm