I have a couple of Motorola gp340 laying around and I wanted to make echolink node using rpi 2 and these gp340. After programming ( it was story for another topic) I wanted to connected it with rpi but I cannot find where is the ptt pin on 13 pin connector. Is there someone who can help me with schematic how to connect mic and put. It really poorly informations on the internet... I found that the ptt is supposed to connect ito the pin 5? (option select 2 pin) but voltage on that pin is 3.2V, as on pin 6 (option select 1). Any information would be appreciated.

Thank you in advance,?

Jovan?

#moto

Pinout for GP340, HT750, others.
Pin number 1 is on cable entry end. Pin 13 is nearest the thumbscrew.

1??? External Speaker+
2??? External Speaker-
3??? Option B+
4??? External Mic
5??? Option Select 2 (PTT)
6??? Option Select 1
7??? Ground
8??? RX DATA
9??? TX DATA
10??? RSSI
11??? Transmit Audio/Rx Audio
12??? Boot Control
13??? Not Used

1K resistor inline with PTT, built into the 13 pin plug of speaker mic.

Pin 6 & 7 connected together, also built into the connector. Often called cable detect.

Etera E980 android based radio uses the same connector for speaker mic, but there are differences in the other connections. Same with Baofeng that also uses this connector on some radios, including dual PTT models.

Regards,

Duane Hall
AB8QU

On 1/20/2025 2:11 PM, jodza77 via groups.io wrote:

I have a couple of Motorola gp340 laying around and I wanted to make echolink node using rpi 2 and these gp340. After programming ( it was story for another topic) I wanted to connected it with rpi but I cannot find where is the ptt pin on 13 pin connector. Is there someone who can help me with schematic how to connect mic and put. It really poorly informations on the internet... I found that the ptt is supposed to connect ito the pin 5? (option select 2 pin) but voltage on that pin is 3.2V, as on pin 6 (option select 1). Any information would be appreciated.

Thank you in advance,?

Jovan?

#moto