Understanding Your Scanner's Modes
22
Motorola systems are trunking 
systems used primarily by 
business and public safety groups 
to efficiently allocate a small 
number of frequencies (as few as 
five) to many groups of users (as 
many as several thousand). To do 
this, each group of users in the 
system is assigned to a specific 
talk group. For example, the east 
side patrol officers might all be 
assigned to talk group 2160. One 
channel in the system is 
continuously transmitting data that 
identifies which talk groups are 
active on which channel. In 
addition, this talk group 
information is also transmitted as 
subaudible data on each active 
channel.
When the scanner receives a 
transmission on a channel set to 
the Motorola mode, it first decodes 
the talk group ID data included 
with the transmission. In the open 
mode, the scanner stops on the 
transmission and displays the talk 
group ID on the bottom line of the 
display. In the closed mode, the 
scanner only stops on the 
transmission if the talk group ID 
matches a talk group ID that you 
have stored in the bank's talk 
group ID list and have not locked 
out.
Motorola trunking systems come 
in three categories: Type I, Type II, 
and Type I/II Hybrid. Each 
category displays and uses talk 
group IDs in slightly different 
ways.
Motorola Type I IDs are in the form 
FFF-SS
, where:
20-525NEW.fm  Page 22  Monday, July 1, 2002  2:58 PM