3
DTXM INPUT/OUTPUT CONNECTORS
DB-15 Connector Pinout
Pin Number
Name
Description
Comments
1
Audio/Mic In
External Audio Input
Wideband input for data.
2
Audio Out
Auxiliary Output
Wideband output for data.
3
Speaker
Audio PA Output
Output of audio PA.
4
CS0
Channel Select low bit
Not used- Firmware disabled
5
RSSI
Receive Signal Strength
Analog Receive Signal Strength
Indicator
6
NC
No Connection
7
DISC Out
Buffered Discriminator Audio
8
RD
Receive Program Data
9
TD
Transmit Program Data
10.
CTS
Clear To Send
Asserted when
transmitter can accept
modulation.
11.
CS1
Channel Select mid bit
Not used- Firmware disabled
12.
Test/PTT
Push To Talk
Activates transmitter.
13.
CD
Carrier Detect
Carrier detect output.
14.
RTS
Request To Send
15.
GND
Ground
Negative supply point and
reference for all inputs.
Pinout Description
Pin Number
Description
1
AUDIO/MIC IN -This is the main audio input for modulation. The gain through
this input to the modulator is programmable, as is the use of pre-emphasis. This
signal passes through the clipper and clipper filter.
2
AUDIO OUT-This is the broadband output of the receiver. The gain from the
receiver to the output is programmable, as is the use of de-emphasis. The
choice of AC or DC coupling from the RF board discriminator is also
programmable. The coupling at the output of this pin is AC coupled, however. It
can be converted to DC coupling with internal hardware modifications.
Note:
The output impedance is approximately 600 ohms. Therefore, it is not
recommended that this output drive loads with less than 1000 ohms unless
the resultant voltage drop is accounted for.
3
SPEAKER -This is the output of the audio power amplifier. This output can drive
up to 100 milliwatts into an 8 ohm load. The output level can be controlled by
programming. De-emphasis can be applied to this output, but not independently
of the AUDIO OUT output. Note that this output level varies with the adjustment
via the programmer of the AUX OUT level. Thus, the AUX OUT level should be
set first before adjusting the AUDIO OUT level.
