12
know both the frequencies used by the system and the LCN for each frequency so that you
can program the frequencies in LCN order.
Agency-Fleet-Subfleet – talk group ID’s for EDACS systems are assigned in a way that
makes it easy to see at a glance the affiliation of the user. Each radio is assigned a 2-digit
agency identifier from 00 – 15. For example, 01 might be used by the police, 02 by
ambulance service, 03 by the fire department, and so on. Each agency is then subdivided
up to 16 times to provide fleet identification, and then 8 more times to identify subfleets.
For example, the complete AFS for the Police Department West District’s dispatch channel
might be 01-062. 01 identifies the agency as the police department, 06 identifies the fleet
as the West district, and 2 identifies the subfleet as the dispatch channel. While these
assignments are somewhat arbitrary and vary from system to system, there are many
resources on the web for finding the assignments for most systems. Because of the logical
hierarchy of the AFS system, your BC898T lets you assign wildcard ID’s that let you, for
example, use only one ID memory to identify all units in either an agency or a fleet.
EDACS SCAT – EDACS SCAT (Single Channel Autonomous Trunking) systems operate
on a single channel and alternate control data with analog voice traffic. While your BC898T
cannot track ID’s in this system, it can eliminate the control data so that all you hear is the
voice transmissions when you monitor this type of system.
LTR Trunking
LTR (Logic Trunked Radio) systems are trunking systems used primarily by business or
private communications service providers, such as taxicabs, delivery trucks, and repair
services. These systems encode all control information as digital subaudible data that
accompanies each transmission, so there is no separate control channel. Users on an LTR
system are assigned to specific talk groups, which are identified by the radio as six digit
numbers.
These numbers are in the form AHHUUU, where:
A = Area code (0 or 1)
H = Home repeater (01 through 20)
U = User ID (000 through 254)
When the scanner receives a transmission on a channel set to the LTR mode, it first decodes
the LTR data included with the transmission. In the ID search mode, the scanner stops on the
transmission and displays the talk group ID on the display. In the ID scan mode, the scanner
only stops on the transmission if the LTR data matches a talk group ID that you have
stored in the bank’s talk group ID list and have not locked out. LTR systems are frequently
programmed so that each radio has a unique user ID. LTR systems also need to be
programmed into your scanner in channel order.
Since many LTR systems use only odd-numbered channel slots, you would program these
systems using only the corresponding odd-numbered channels in a bank (for example,
