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Understanding Scanning
can begin speaking. This all typically takes place in about
a second...the person transmitting hears a beep from
their radio when the channel is assigned and then it is OK
to start talking.
The systems in use are:
Motorola Type I – the radios send the radio ID, the fleet
and subfleet talk group ID to the control channel each
time they transmit. To program a Type I system, you need
to know the system’s fleet map. The most common fleet
maps are included in “Preset Fleet Maps” on Page 105.
You can also find fleet map resources on the web.
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.
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.
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 BC246T can monitor.
Logical Channel Numbers – each frequency used by the
system is assigned an LCN. This information is pro-
grammed 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