Service manual

EXTERNAL SERIAL CONTROL PROTOCOL
B-28
April 2001
Part No. 001-9800-203
Format:
Bandwidth
: I/F bandwidth:
0x00 - Narrow
0x01 - Wide
CMD SET POWER LEVEL
Function
: Requests that the subscriber unit select the
requested RF power level. The protocol supports
five power settings; however, some units may only
allow two in which case all “low” settings are the
same. The exact power level for each is set by radio
tuning.
Format
:
Power
: RF Power Level-
0x00 - High
0x01 - Low Power Setting 1
0x02 - Low Power Setting 2
0x03 - Low Power Setting 3
0x04 - Low Power Setting 4
CMD START TX
Function
: Requests that the subscriber unit begin
transmitting. If the TRANSMIT EVENTS notifica-
tion is enabled, an EVENT TRANSMIT message is
sent. Normally, the subscriber unit does not
transmit on a busy channel (squelch is open).
However, a transmit condition may be forced by
setting the force option on.
Format
:
Force transmit
:
0x00 - Transmit only if channel is not busy
(squelch closed)
0x01 - Transmit always
CMD STOP TX
Function
: Requests that the subscriber unit stop
transmitting.
Format
:
Data
: None
CMD SET SQUELCH CIRCUIT
Function: Sets the value that is output to shift register
U305 to control the trip point of a comparator in
the squelch circuit. Squelch levels may vary from 1
to as high as 255. The command is NAKed if the
subscriber unit is scanning or not currently using
conventional signaling The change is not saved in
memory.
Format
:
Squelch Circuit
:
0 = This is an invalid level. The command is
NAKed if it is used.
1-255 - Valid squelch circuit levels. The command is
ACKed.
Opcode Bandwidth
1 byte 1 byte
0x26
Opcode Power
1 byte 1 byte
0x27
Opcode Force
1 byte 1 byte
0x29
Opcode
1 byte
0x2a
Opcode Squelch Circuit
1 byte 1 byte
0x2f