ABCs of Trunking

The following compilation has been created to help demystify many of the terms and acronyms of the trunking business. Click on the first letter of a word or acronym for definitions.

 

0-9 | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P |Q | R | S | T | U | V | W | X | Y | Z

 

0-9

3GPP

The 3rd Generation Partnership Project (3GPP) is a collaboration between groups of telecommunications associations, to make a globally applicable third-generation (3G) mobile phone system standards.

3GPP.org

821

If this is marked "Y", this radio unit can operate on 821Mhz frequencies.

A

ACTivate

In the SAC section of Guardian, this puts a unit or range of units in a list of active, in use units that are allowed access to your system.

ADCC

Analog/Digital Cross-Connect. A network device used to switch and multiplex low-speed voice and data signals onto high-speed lines and vice versa. This is integral in a Motorola Connect Plus system.

AFF

Short for affiliation. This helps group groups of radios together. In a system with TypeII IDs, you can have Talk Groups. These talk groups can be "affiliated" with each other with this command. Airtime: The time that a unit or group of units uses for either dispatch or interconnect during a given period, such as a month. Usually given in minutes.

AMNP

Accounting and Management Network Protocol is the interface for the P25 Network management protocol standard supported by Genesis.

AMS

Automatic Multiple Site Switching. This will allow the unit to make a wide area (AMSS) call.

ATIA

Air Traffic Information Access. In a Motorola SmartZone system, this is an ethernet port that streams information about usage on the system.

AUTH

The location in Guardian where interconnect units are given authority to use the CIT so they can make phone calls. This is also where the CIT will provide the 4 or 6 digit extension number for a mobile.

Auth Level

Available in Guardian under the AUTH prompt. When adding a unit to AUTH, the user is asked a question: "Auth Level? (1-5)". The different levels mean:

1 = No calls are allowed but a place is held in the AUTH list.

2 = Calls that are free to the local area code as well as any nearby area codes (set up in MEXC) are allowed.

3 = Free and "unit calls" to exchanges in the local area code or nearby area codes where you have set up billing instructions in the MEXC are allowed.

4 = All exchanges in the local area code as well as all exchanges set up in the nearby area code section of MEXC are allowed.

5 = Calls to anywhere are allowed. They are wide open. What the unit can actually dial is very dependent on how the MTEL and MEXC sections are configured. It is also dependent on a "Yes" or "No" answer to Enable 1+ Dialing and Enable 0+ Dialing.

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B

BILLING

This is a logon level in the central controller that allows the person logging on to all billing type commands.

Blockage

When a unit cannot get access to a channel on the trunk system. This is indicated by a busy signal in the mobile.

BSI

The Morse Code version of an FCC call sign. The controller sends this out over the lowest frequency channel on a trunk system every half hour.

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C

Central Controller

Same as controller. The brain of a trunking system.

CHAN

Short for Channel. This is the section of Guardian where you can see if a channel is working, disable a channel, enable a channel and find out which channel is your Control Channel. In TypeII Guardian you can do this for a block of repeaters rather than one at a time.

CIT

Central Interconnect Terminal. This was also known as the PassPort. This is the hardware that makes telephone calls possible.

CLOAD

This command Loads the picture of the CSC memory that you saved with the CSAVE command, back into a central controller.

Coax

The "pipe" that takes the signal from the antenna to the radio, and from the radio to the antenna.

Controller

The "brain" or computer that makes all of the channels trunk together. In Motorola systems, Guardian resides here.

Control Channel

The RF channel that is used to communicate to all of the mobiles. This tells the mobiles about incoming telephone calls, what channel to go to for dispatch and interconnect calls, and other more technical things. It will always be on channel one, two, three or four.

Control Station

Sometimes called the Base. This is generally the radio that sits at a customer's office where most of the "dispatching" is done.

CSAVE

Short for CSC Save. This sends a picture of the entire CSC (dispatch section) to your computer. EzSaveII can automate this for you.

CTI

Centralized Telephone Interconnect. Same as CIT. Some people call it CTI, some call it CIT.

Cursor

This is not an angry football fan. It is that little underline ("_") on a screen that flashes.

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D

DAT

Data Request. This enables the unit to make a data request.

DEA

Deactivate. In Guardian under SUBS or SAC this is where you can turn a unit off by removing him from the list of radios that are allowed to use the system. To temporarily turn a unit off you need to EDIT the unit and make ENA="N".

DIAG

Short for diagnostics. This is a section in Guardian that generates, stores and prints error messages.

DID

Direct Inward Dial. This is a 7 digit phone number like 880-4600. The PassPort CIT by itself has to be used in a "overdial" mode where 4 or 6 digits are dialed after a main inbound number to the CIT is called. With the addition of a device such as a Hark SI-550, every telephone unit can have its own 7 digit DID so "overdialing" is not necessary. Appropriate circuits need to be arranged with your phone company for all of this to work. The MBX interconnect has DID built in to it.

DIU

The Digital Interface Unit steers voice messages to the console and data messages to the radio network controller.

DRG

Dynamic Regrouping. This enables the unit to initiate dynamic regrouping commands (open gateway). Check OPT to see if your version of Guardian allows DRG. This allows mobiles in one fleet on a temporary basis, to talk to units in another fleet.

DVP

This is the Secret Service stuff. Radio units equipped to make DVP calls scramble the voice so it can only be understood by a certain radio on the other end of the conversation. These radios can scramble on dispatch or interconnect.

Duplex

A duplex communication system is a system composed of two connected parties or devices that can communicate with one another in both directions. The term multiplexing is used when describing communication between more than two parties or devices. Duplex communication is the way a typical residential telephone works. A walkie-talkie is only half duplex (simplex) because only one transmission can be heard at once.

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E

EMRGency

Some radios are capable of making emergency calls. How these calls are handled can be set in the Guardian under the EMRG section.

ENA

This stands for Enable. If you answer Y this will allow that individual to use the system when the Subscriber function is active.

EP2

Enhanced Protocol IIi. This tells you that the individual does not perform high speed handshake. For Type II units, this flag will always be set, and cannot be modified since these units never perform high speed handshaking.

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F

FIX

Fixed Location. If you answer Y it indicates that this individual has a fixed location, maybe a console. If you answer N it means that the individual has a mobile location.

Fleet

Loosely defined, this is a company using a trunk system. Specifically a fleet is a grouping of radio codes that can, if properly coded, talk to each other. (See Subfleet)

Full Duplex

The ability to send and receive data simultaneously which, in digital audio terms, translates to being able to play and record audio at the same time. For more on duplex communication, see Duplex above.

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G

GGSN

The Gateway GPRS Support Node (GGSN) is a main component of the GPRS network. The GGSN is responsible for the interworking between the GPRS network and external packet switched networks.

GOSMR: Government Owned SMR GRD>: Guardian

This is the prompt you see after calling into the central controller with a computer terminal.

GPRS

General Packet Radio Service (GPRS) is a packet-oriented mobile data service that connects users to a Public Data Network (PDN). Within the GSM network it shares the network databases and radio access network. As a billing gateway, it's fees are typically based on call volumes.

GTP

GPRS Tunneling Protocol (GTP) is a group of IP-based communications protocols used to carry General Packet Radio Service (GPRS) within GSM and UMTS networks.

GSM

Global System for Mobile Communication is the most popular standard for mobile telephony systems in the world.

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H

Hark

The name commonly associated with a device that allows DID on the PassPort CIT. Hark is actually the name of a company that manufactures several pieces of hardware to enhance the telephone side of Motorola trunking systems and paging systems.

HEX

A method of counting with a base 16 system. Normal counting goes from 0 to 9. Hex goes from 0 to F. Motorola uses HEX numbers for all IDs.

HPD

Motorola High Performance Data (IV&D) which simultaneously conveys data and voice over one network. See IV&D.

Hybrid System

In the Motorola trunking world, this is a system that has both TypeI and TypeII IDs operating on the system.

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I

INT

Interconnect Call. Answering "Y" allows a unit to make interconnect calls. The unit must be capable of making an interconnect call, and must be on the authorization list if it is active. Interconnect: A big word for making a telephone call to or from a radio unit.

ISDN

Integrated Services Digital Network (ISDN) is a set of communications standards for simultaneous digital transmission of voice, video, data, and other network services

IV&D

Integrated Voice and Data uses a digital conventional radio network to transport voice and data information over the same channel to mobile radios and data terminals in the field. This unique approach enables wireless data applications and eliminates the need for separate data networks and radios for voice and data. Genesis software operates within the 3GPP mobile broadband standard.

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L

Land to Mobile

This is a number AUTH gives you when you turn on a unit for interconnect. This is also called the Overdial number and Extension number.

LIMits

Under the SERV command in Guardian. This allows you to play with the Shared Use Parameter table to suit you needs. Warning: Only for very experienced experts!

LINK

In the trunking world, this refers to microwave or phone line links that tie one central controller in one location to another. This could be a backup central or part of an AMSS system.

Local Level

Question in Guardian under AUTH. In the MTEL section you set up limits in dollars for Local levels 1-4. In theory, if you set MTEL so Level 1 has a $10.00 limit, if the unit uses more than $10.00 with of local telephone line time (reported in the STEL) then his unit will stop operating. Again, this is just in theory. Just set high dollar amounts and set all units to level 4. You'll be just fine.

LOGN

The opposite of LOGY. This tells Guardian to stop logging ALL calls and to log only those that are considered as long distance.

LOGY

Log All Calls "Yes". This tells the CIT to make a listing in the SLNG report for ALL calls, not just long distance. The upside is that you can give a customer a call detail report that shows local and long distance calls. The downside is that the relatively small call buffer in the CIT fills up fast with all calls being logged and must be dumped very often.

LRRP

In this instance, LRRP does not refer to Long Range Reconnaissance Patrol. The Location Request and Response Protocol — part of Motorola's Outdoor Location Solution (OLS) — is how Genesis communicates with the Motorola Universal Processing Server (MUPS).

LTE

Long Term Evolution is the latest standard in the mobile network technology. It is a project of the 3rd Generation Partnership Project (3GPP). The main advantages with LTE are high throughput, low latency, plug and play, an improved end-user experience and a simple architecture resulting in low operating costs.

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M

MANUAL

In the TypeII (newer) Guardian, this is where you can have the DIAG messages given to you on demand instead of as they happen.

MASTER

This is the highest level password into a Type II (newer) Guardian system. This allows you to do anything in the system. (see CONTROL, BILLING, and SYSTEM)

MBEX

Motorola Business Exchange This is a Motorola, Inc. trademark). This is a new version of the CIT (PassPort) that Motorola is offering. It has capacity for several thousand telephone units, digital audio processing, DID, least cost routing of calls and more. This is also called an MBX in many cases.

MCSMR

Motorola Controlled SMR (they manage the SMR for a private owner).

MESMR

Motorola Entrepreneur SMR.

MFL

In Talk Groups, this indicates if the Talk Group is made up of TypeI and TypeII IDs.

MGC

Multi Group Call. This allows the unit to make multi-group calls (fleet-wide/announcement). Mhz: Pronounced "mega hertz". Literally this means million cycles per second. The Hertz comes from the man that discovered that things can vibrate in cycles every second. We measure frequencies in Mhz like 823.0375Mhz.

MLOAD

Under the AUTH section of Guardian, this allows you to reload the information saved to your computer with MSAVE. You would do this if your system crashed.

Modem

Modulator-Demodulator. This is the little box with flashing lights that allows your computer to communicate over telephone lines with a remote location. This can also be a card that is internal to a computer with no status lights.

MOSMR

Motorola Owned SMR.

MSAVE

Under the AUTH section of Guardian, the MSAVE command creates a snapshot of all interconnect related memory. This will not capture the SLNG records.

MUPS

The Motorola Universal Processing Server is a gateway for the location, telemetry, and presence information from ASTRO 25 radios. It transfers data to any back-office applications. Additionally, it routes requests and commands from the back-office application to the devices.

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O

OmniLink

This is an ultra-wide area Trunking scheme developed by Motorola. Individual sites can be linked together into a SmartZone system. SmartZone systems can then be linked together into an OmniLink system.

OPT

Option List. This command is available in Guardian under the SUBS or SAC prompt. This will let you know what your version of Guardian is capable of doing. Not all SUBS or SAC options are available on all systems. By the way, we've also found that some systems will improperly report the OPT list. Thought you would like to know!

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P

PAG

Paging Request. This enables the unit to make a paging request. PassPort: Also known as the Central Interconnect Terminal. This is the hardware that makes phone calls possible both in and out of a trunk system.

PDG

The Packet Data Gateway is a 3GPP functional entity which is responsible for supporting 3G to WLAN (Wireless LAN) interworking. Key functions of the PDG include traffic security, IP address assignment, authentication, accounting and QoS enforcement.

PDN

A Public Data Network is a generic term for a network providing data services, such as the Internet.

PDIGIT

A command in AUTH section of Guardian. This allows you to tell your CIT to ignore up to 5 digits that are dialed before the actual number. Some phone companies (the older ones) are looking for a special "circle dialing digit" before any call is processed.

PMG

In talk groups, this indicates if the group has Priority Monitor capability.

PRL

Priority Level. This is available in Guardian under the SUBS or SAC prompt. If OPT says that you can change this number, you can set this level (2-8) to for each individual. This allows one mobile to have faster access over another. This generally applies to a mobile waiting in a queue.

PROTECT

In the TypeII Guardian, this marks a channel so that the central will make it the last choice for servicing a call request. The protected channel will be selected only if all other possible choices are busy. Why protect? If a particular channel is giving off or receiving interference. Keep a paging channel as free as possible. Keep a secure equipped channel as free as possible, and so on...

PTI

In Talk Groups, this indicates if the groups is capable of Push To Talk ID. This option is usually only active if there is a console attached to the trunk system.

PTT

Push To Talk.

PVC

Private Call. This allows the unit to make a private call. The unit must be equipped with one of the private call options. This is a silent way for one mobile or control station to call another mobile. The unit selects a switch position, presses his microphone and a signal is sent on the Control Channel to the destination mobile. A special beeping is heard in that mobile.

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Q

Queue

Pronounced "Q". A waiting line. Inside the Motorola Trunk system there are three that are important to you. There's a dispatch queue, recent user dispatch queue and Telephone queue. When a unit is put into a queue, he will hear beep-beep-beep in his mobile. If he will just wait, he will come out of the queue in generally a FIFO (first in first out) basis. Not all Trunking system manufacturers offer an orderly queue system.

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R

Repeater

Literally, the device that receives and re-transmits. If your trunk system is a 5 channel system, you have 5 repeaters. If you have a 20 channel system, you have 20 repeaters. At this time, one conversation takes place on one repeater. Call the X-Files.

RF

Radio Frequency. For trunking systems, this is usually in the 800Mhz or 900Mhz band. The signals are carried through the air over these "R.F. carrier frequencies". It's a strange, mystical phenomenon, really.

RIB

Receiver Interface Board. This ties the repeater receivers to the Central Controller for dispatch traffic.

Roamer Fleet

Since there are many units that like to work in a wide area, they need to "roam" in and use a trunk system for a short period of time. Rather than setting up a separate fleet for every single user, the roamer fleet groups them all into one fleet so the "memory map"

Roamer

A unit that occasionally uses a system. This can be a single unit that uses a system only for interconnect or a group of units that uses a system for dispatch, or all of the above.

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S

SAC

Subscriber Access Control. On Guardian Type II Central Controllers, this is the prompt for adding units to "positive subscriber".

SAIR

Summary of Airtime. This is available from the Central Controller under the BILL Prompt. In this report, every Authorized unit gets a one line listing showing how many minutes it talked during a particular time period (usually a month).

SEC

(Secure Communications). N (Normal) indicates that the talk group is allowed to make clear (non-coded) calls only. S (Secure) indicates that the talk group can make secure (coded) calls only. B (Both) indicates that the talk group is allowed to make both clear and secure calls.

SERV

Service Algorithm. This is where you can set the length of interconnect calls, the priority given to interconnect and dispatch. Also you can get the system Statistics report from this prompt.

Shared User

This can be complicated! This is a concept where certain radios or groups of radios can be steered to certain repeaters. You can use this to let a local municipality share your central controller, add their own repeaters and at the same time use your interconnect (all for a fee). There are many combinations. You can have up to 8 groupings like this.

SHU

(Shared User). Individual users are grouped into one of eight shared user groups (A-H). If your version of Guardian allows this, you can have up to 8 distinct separate entities using your system on a shared basis. Example: Group A would be all of your SMR customers on their individual fleets. Group B could be your local City's police department. Group C could be a local Red Cross. This is very flexible.

SITE

In TypeII Guardian (the newer one), this is specific to multi Central Controller systems. Most MESMR operators can ignore this.

Simplex

Also known as half duplex, it is the opposite of duplex. Two-way dispatch conversations are simplex. The operator pushes a button to talk and then releases it so he can listen.

Skip

A phenomenon that happens (for 800Mhz) early in the morning where other radio signals from over 100 miles away interfere with your trunk system. (SEE Tunneling)

SLNG

Summary of Long Distance. Available from the Central Controller under the Bill Prompt. As with the STEL, what is reported in the SLNG is very dependent upon how the CIT is configured. At a minimum it will list all long distance calls (1+ and 0+). At the maximum setting, it will list all calls that are made (see LOGY).

SMR

Specialized Mobile Radio. This is a term that the FCC attached to the "for public use" trunking business. If a company has a wireless trunking backbone system that is open for use by the general public (for a subscription fee), then they are an SMR.

SNMP

Simple Network Management Protocol (SNMP) is a UDP-based network protocol. It is used mostly in network management systems to monitor devices for conditions that warrant administrative attention. SNMP is a component of the Internet Protocol Suite.

STATS

This is a listing of your system performance in 15 minute intervals over a 24 hour period. This shows quantity of dispatch and interconnect calls, quantity of busies, etc.

STEL

Summary of Telephone. Available from the Central Controller under the BILL Prompt. This is actually only the Summary of Local Telephone usage. How many local calls a unit made as well as any charges for those. The charges that show up are very dependent on how you set up your Central Controller TEL parameters (MTEL, LTEL).

Subfleet

A portion of a fleet. As an example, a construction company might have their own fleet and then break it down into several subfleets. This way the electricians can talk while the plumbers are talking. Also, they won't hear each other. Many companies use subfleeting to allow supervisors talk to each other without the worker bees listening in.

SUBS

Subscriber Access. In TypeI (older) Guardian systems, this is where you Activate units and allow them to talk dispatch (and/or interconnect) (See SAC) SYSTEM: This is a logon into the central controller that is generally given to service personnel. With this logon, they can view anything but they cannot change anything.

System ID

The 4 or 5 digit number that Motorola assigns to a Central Controller (System). This is the main number that identifies one trunk system from another.

System Manager Terminal

The term Motorola uses for your computer at your office that you use to call your trunk site. There is also a thing called the SMT port on the controller. This is where you hook your modem or computer to talk to the controller.

SYW

System Wide. Allows the unit to make a system wide call if it is equipped with the system wide call option. With this option, a control station or a mobile can make an announcement to every radio on your trunk system. This can be used to announce that the system will be down for repairs, etc.

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T

Talk Group

This is similar to a fleet but technically is more analogous to a subfleet. It is a grouping for radios that normally talk together in a one-to-many arrangement.

TCMS

Trunk Code Management System. In the early days of Trunking, Motorola controlled every ID that was put into every radio in the world. This was done in Schaumburg, Tokyo and Israel. In the mid '90s, their focus had changed and the shut down the TCMS system. Now, managing IDs is left to the system owner. Motorola still manages the IDs of the systems that they manufacture and ship.

TEST

In Guardian, this is forces the trunk system to check all of its vital components and report their status in the form of DIAG messages. There is another command that does a better job of testing and resetting the system. If you're curious, e-mail us!

TGW

Talk Group Wide. This allows the unit to make talk group wide calls.

TIB

Transmitter Interface Board. This ties the transmitters to the Central Controller for dispatch traffic.

TRAN

This is located in the interconnect part of Guardian. When units are added to the AUTH list in TypeII Guardian they are assigned a 6 digit overdial number. The TRAN table allows you to preserve the old 4 digit overdial.

TRIB

Transmitter Receiver Interface Board. This ties the CIT or MBX to the repeater transmitters and receivers.

Trunking

In its basic definition, this is a method of permitting a high number of conversations over a lesser number of communications paths. Every time you pick up a telephone to make a call, you are using "wired" trunking system. The trunking we use is wireless using radio waves. To accomplish this trunking, either wired or wireless, a smart device like a computer is needed. In Motorola trunking, this is called the Central Controller. In the LTR world, it is called a Validator.

More about trunking

Tunneling

Like skip, this is when the atmosphere "flips" over and allows radio signals to travel long distances. This generally happens in the early morning hours when the sun comes up. The upper atmosphere warms before the ground air and this causes a "tunnel" where the signals bounce up and down close to the ground. This lets them travel long distances and then interfere with other trunk systems. Maybe yours!

TypeI ID

In early Motorola Trunking, IDs had certain limits. Some fleets could only have up to 16 radios while others could have up to 512 radios in the fleet. As the success of analog Trunking caught on, This proved to be restrictive and TypeII IDs were invented. All TypeI IDs are indicated as HEX IDs on all documentation.

TypeII IDs

This is the newer system of identifying radios on a Motorola Trunk system. Valid IDs can go up to 65535 or so. They are represented in all documentation as I7xxxxx (xxxxx is a decimal number from 00001 to 65534). There are no limits on the quantity of radios that can be in a fleet.

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U

UDP

User Datagram Protocol. With UDP, computer applications can quickly send messages. Voice and video traffic is generally transmitted using UDP.

UEM

Unified Event Manager.

Unit ID (full)

The combination of the System ID, Fleet ID and the actual Unit ID.

Unit ID

The last digits of the full unit ID that indicate the ID of the actual radio. For a TypeI ID, this is a 3 character hex number. An example of a TypeII ID is I7xxxxx where xxxxx is a 5-digit decimal number.

UMTS

Universal Mobile Telecommunications System.

UPDATE

This is in the AUTH section of Guardian. After you add or edit units in the AUTH list, they are not actually added or edited until you type UPDATE or until you exit the AUTH section.

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V

VER

In the Guardian system, this displays the version number of your software.

Validator

A term used for the 'brain' in LTR style Trunking systems. Most validators contain a list of codes that are permitted to operate on a given system and they also record airtime and telephone usage information for billing purposes.

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Z

Zone Controller

In a Motorola SmartZone system, this is the "brain", or controller, that commands all of the other controllers that are located at the individual sites.

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