Vertex Standard VX-2500V - Manual (Page 3)

3
DSUB 9-pin Accessory Connector
Pin 1: Output Logic squelch
High: Radio receiving the signal with the correct CTCSS, DCS, or LTR ID.
Low: Radio not receiving the signal with the correct CTCSS, DCS, or LTR ID.
Pin 2: Output Rx discriminator
JP3 (JP1503) - Flat: 10 Hz to 3.0 kHz (140 mVrms / STD deviation with 600 ohm termination)
or
JP4 (JP1504) - Filtered 300 Hz to 3.0 kHz (70 mVrms / STD deviation with 600 ohm termination)
* Note: JP3 is closed from the factory, and JP4 is not closed from the factory.
Pin 3: Input TX data to the radio modulator. (Flat: 10 Hz to 3.0 kHz)
(40 mVrms / STD deviation)
Pin 4: Input DTR (to switch the radio operation between dispatch operation and Data mode)
[DTR Low: Turn on the Data transmission, less than 0.5 V]
[DTR High: Turn off the Data transmission, more than 4.0 V]
Pin 5: Ground
Pin 6: Output Horn alert signal (Open collector with maximum 16.0 V, 100 mA sink).
Pin 7: Input external PTT
[Low: Request the transmission]
[High: Request the Receiving]
Pin 8: Output supply voltage (Need to set the solder short on the PCB)
JP1 (JP1501) Output 5.0 V (Maximum 100 mA output)
or
JP2(JP1502) Output 13.8 V (Maximum 100 mA output)
* Both JP1 and JP2 are not closed from the factory.
Pin 9: Input the ignition signal of the CAR.
This signal is for the following operation,
(1) Disable the Horn alert during the ignition is turned on.
(2) Turn on and off the radio. This function requires the solder short JP8 (JP1508).