Motorola ENLN4056 Manual page 8

Functional Description
1.1.5 Channel Change
The TRICK supports two methods of channel change;
SBEP Channel Change
The primary method of controlling the radio channel number is by sending SBEP (Serial Bus
Extended Protocol) commands via the radio serial bus. On the GM350 and GM950 mobile radios,
the serial bus is accessible via the radio accessory connector.
Using the serial bus, the TRICK is able to steer between a maximum of 4 channels for 4-channel
models and 8 channels for 128-channel models.
Parallel Channel Change
As an alternative to using the serial bus, channel control may be achieved by programming the
general purpose input/output pins on the radio accessory connector for channel steering.
The ability to change channels using the parallel inputs on the radio accessory connectors is
provided to support Motorola mobile radios which do not allow external access to the serial bus
(eg. GM300).
Using the parallel channel steering lines, the TRICK is able to select a maximum of four channels.
See the Installation and Programming Guide for further details.
1.1.6 Repeater Operation
The TRICK may be programmed via the RSS to support three types of repeater functionality. The
difference between the repeater types concerns the conditions which must be met to enable
re-transmission of a received signal.
The following sections provide a definition of the terminology involved, followed by descriptions of
the three types of repeater.
1.1.7 Repeater Terminology Definitions
The repeater may be in one of three states during operation; "Knocked-Down", "Set-Up" or
"Enabled".
Enabled - means that the repeater is actually re-transmitting received "Valid Audio". The repeater is
enabled only for the duration of the conversation (ie: once the TOT or Hang Timer has expired, it will
be necessary to re-enable the repeater).
Valid Audio - is indicated by the receive radio via a signal on its accessory connector CSQ/PL
detect pin. Depending upon the application, the valid audio signal may be either CSQ or PL/DPL
activated.
1-4 Functional Description & Applications