Installation ......
CM1481 Radio Interface
The table below shows the functions and interconnections of the CM1481 interface (J1) employed in both
NORMAL
and
CONFIGURATION
modes.
Functions prefixed by a star (*) indicate configurable IN/OUT polarities. Consult the Configuration section of this
*
manual for Configuration Instructions and Configuration Interface Connector termination information.
Pin
1
2
Function
CONFIG
*
BUSY
Normal Mode - to Radio
Function
Configure Mode - to PC
Configuration mode sense. When this pin is “High” the module WILL NOT enter the
CONFIGURATION
mode, when “Low” the module WILL enter the
CONFIGURATION
mode on power-up.
Input from the radio squelch circuitry. A level here
indicates the presence of an RF carrier.
Input from the installation “Operation” momentary-
action switch to initiate a Selcall.
See "Single/Dual Button" Operation notes.
CLOCK
The CLOCK signal generated by
the configuring PC is input here.
3
*
Tx CALL
4
*
QUIET/OPEN
Input from the installation “Operation” momentary- DATA IN
action switch to control the radio mute state.
See "Single/Dual Button" Operation notes.
Input from the Mic. or peripheral PTT line.
The CM1481 controls the radio Tx function via
Tx On.
Input for received Selcall tones from the radio
demodulator prior to squelch circuitry.
Audible alerts output. Introduce into the radio's Rx
audio stage with due regard to any audio powersave
functions. This output can drive a loudspeaker directly.
Output drive to an LED indicator.
Connect an LED between this pin and GND.
Selcall tone output. Introduce this output into the
radio Tx Audio path.
Connect to radio Rx Squelch circuitry so that when
this output is active Rx Audio is muted.
Tx PTT Drive. When active this output will key the Tx.
Signal Ground (-)
Positive Supply Voltage (+)
Data from the configuring PC to the
module is input here.
5
*
PTT IN
6
SIGNAL IN
7
ALERT
8
*
LED
DATA OUT Data from the module to the
configuring PC is output here.
9
TONE OUT
10
*
MUTE CTRL
11
12
13
*
Tx ON
GND
V IN
AUDIO SWITCH
An on-board (Audio Signalling Processor) all-audio switch-path, accessible via on-board
solder-pads. This switch operates in co-ordination with the QUIET/OPEN function for use with all audio
signals. When 'Quiet' the switch is OFF, when 'Open' the switch is ON.
Table 1 CM1481 Radio Interface Functions
The position of Pin 1 is identified on Figure 4 (PCB Layout).
5
CMLMICRO [ CML MICROCIRCUITS ]
