User's Manual
z Motorola Type II – the radios only send the radio ID and radio
channel code to the control channel. The central computer
keeps a database of radio ID’s and which talk group is
assigned to which channel code for each radio, so with this
system the user’s radio sends only about 1/3 the data as a
Type I system with each transmission. Type II systems do not
use Fleet-subfleet talk groups; instead they use a 5-digit ID for
each talk group.
z
Type IIi Hybrid — these systems support a mix of both Type I
and Type II users. Like Type I systems, you must know the
system’s fleet map to ensure proper tracking.
One big difference you will notice with digital versus analog
transmissions, is that with analog systems, you might be able to
hear weak signals interspersed with hissing. As you move further
away from the system, the interference gradually increases until
you are unable to make out the transmission. With digital systems,
the cutoff point is much more abrupt. You might have a small area
where partial decoding occurs...in which case you will hear partial
and garbled audio. However, once the scanner is unable to receive
the data well enough to decode it, the audio stops entirely. For the
best range, antenna selection and placement is critical. See For
Home Use (Desktop Installation) for more information.
EDACS Trunking
EDACS trunking works in much the same way as Motorola trunking
with a couple of major differences. In an EDACS system, each
frequency used by the system is assigned a Logical Channel
Number (LCN) so that less data needs to be transmitted by the
control channel. Also, talk groups are assigned in an Agency-Fleet-
Subfleet (AFS) hierarchy. Also, there is one variation of EDACS
called SCAT that your BC898T can monitor.
z
Logical Channel Numbers – each frequency used by the
system is assigned an LCN. This information is programmed
into each user radio. When a user presses PTT, their radio
sends their AFS information to the control channel. The
computer then assigns that talk group to a channel and sends
the LCN so that all other radios in that talk group will switch to
the correct channel. To program an EDACS system in your
scanner, you will need to know both the frequencies used by
the system and the LCN for each frequency so that you can
program the frequencies in LCN order.
z
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.
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