9
Raveon Technologies Corp.
9
TXD
TX data in, RS232 level
10
CTS
CTS, 3V digital level
11
NC
No connect
12
PTT
Transmitter Enable Line. Active low. Input impedance is 10K.
TX Mode: Input < 2.9V RX Mode: > 3.0V or open circuit
13
NC
No connect
14
DCD
Data/Carrier Detect output. 0-0.1V no carrier, 2.2K pull-up resistor
to VIN when carrier is detected. The 2200ohm pull-up resistor is
driven by a MOSFET pulling it to ground when no carrier is present.
With a 12V DC input, this output can go to 12V.
15
GND
Ground, chassis and power gnd.
Pin 12 is the Push To Talk (PTT) input. It has a pull-up resistor of about 10K on it.
When PTT is low, the transmitter in the M8T will turn on, and output the audio signal on
pin 1.
When PTT is high, the M8T is in the receive mode, and the receive audio will be output
on pin 2.
On Tech Series products utilizing M8 radio modules, the PTT can be set to active high
via the
ATPTT
command.
There are a few commands designed specifically for use in configuring the operation of
the M8S in audio pass-through mode.
AFDC
Audio input DC offset – The DC bias level on the audio input in millivolt.
Adjust this setting so the audio transmissions are on the center of the
channel. Set to 0 to have the M8S auto-detect the average.
Range: -2000
- 2000
mV
0
AFLVL
Audio input level gain – internal gain of the audio input signal, in % .
Adjust this setting for the audio input deviation level.
Range: 0-
2000%
mV
100
