APCO Association of Public Safety Communications Officers. A national organization of communications professionals that supports and promotes public safety communications concerns.
Control Channel Communication channel implemented by a base station or repeater used to transmit and receive channel assignment data or process other control commands from the system. Contrast with a base station or repeater functioning as a voice channel used to transmit and receive voice information.
DIGITAC Digital Voice Protection Total Area Coverage. A comparator used for audio voting in 12 Kbps secure or clear analog systems.
Emergency Call The highest priority service of talkgroup call. When the emergency button of a subscriber unit is pressed and the PTT pressed, an Emergency Call is granted.
Failsoft A fallback means of communication if a site or subsystem cannot perform wide-area or site-trunking operations. In standalone remote sites and receiver voting sites, the repeaters generate the failsoft word. In Simulcast subsystems, the prime site Universal Simulcast Controller Interface (USCI) generates the failsoft word.
FCC Federal Communications Commission.
Multigroup Announcement Group A collection of two or more talkgroups.
Primary Talkgroup Unique talkgroup parameter in the subscriber radio.
Prime Site The central controlling site of a trunked Simulcast system where all audio processing and channel resource management occurs.
PTT Button Push to Talk Button. Button on a radio the user presses in order to transmit voice information.
PTT ID Push to Talk Identification. A talkgroup programmable function that allows dispatchers to know who is calling and allows each user's call to be logged.
Repeater Station at a master site or remote site that broadcasts and receives RF signals to and from mobile and portable radios in the field.
RF Radio Frequency.
Ruthless Preemption A method of acquiring a channel for an emergency call in a busy condition. A call with a lower priority is terminated to release a channel for assignment to the emergency call.
Simulcast A wide-area trunked system configuration that uses multiple transmitter and receiver sites to extend coverage of the system. All the corresponding channel numbers at all the sites use the same frequency.
Talkgroup A group of radio users that can share calls and messages as a group. A talkgroup comprises a group of users who have a need to communicate with each other.
Talkgroup Call Call involving other users within the originating user's own talkgroup.
Talkgroup ID Unique identifier assigned to each talkgroup in a Motorola trunking system.
Talkgroup Scan A feature that allows a subscriber unit to scan those talkgroups that have an affiliated member at the scanning radio's site. The Talkgroup Scan list(s) must be programmed in the radio.
TG Talkgroup.
Trunking A method of sharing a small number of communication paths among a large number of users.
Unit ID Unique identifier assigned to each radio in a Motorola trunking system.
VRM Vehicular Radio Modem.
Zone Controller Handles the call processing, mobility, and some network management functions in an OmniLink system. Each zone in an OmniLink system has a Zone Controller.
Zone Master Site A Master Site containing a set of zone control equipment comprising a single zone.