Batboard

Hi all,
I'm after some advice.... I'm wanting to interface my uhf motorola gm900 up but I'm unsure what the pin outs are on the accessory connector that connects to the radio....

I've noticed they's not a right lot of info out on the 900's like they is with the gm300's which I did find a pin out diagram for the 16 pin connector to the 300 & it worked quite well using the comport keyer to ptt the radio however I'm wanting to do the same with the gm900 just don't know where to start with it having the 25 pinout & the lack of info that's available to tell me what pin does what.

Any help would be very much appreciated, thanks:-)

Hi again all,
Ok I've read & heard various things relating to the pin layout of the motorola gm900 but everything is different what has been mentioned, I'm wanting to interface one up so I can run an Internet gateway but don't want to start in relation to the pins.
I did interface a gm300 up without any probs as they were plenty info available on the net but just carn't get my head round where to start with the gm900.

From the accessory connector i see that if I'm right pins 1 & 2 are connected or looped together to enable the internal speaker & 4 & 9 are looped together & that's it,
Someone must know that can advise me

Thanks in advance

The following link has the information that you need:
http://batlabs.com/gm900.html

Ok struggerling now, got it interfaced up from the accessory connector to the ptt interface & dedicated my pin 21 for ptt but where in the software do I define pin 21 for ptt?? Can anyone please advice??

Thanks in advance

Hi again,

Ptt is now working but now have another new problem in relation to audio.

I'm using an M0AQC comport keyer to provide ptt to the radio which is now working well but the audio back to the radio sounds very quite via the jack lead that's also routed via the interface & connected to the relevant pin at the bottom of the radio for AUDIO IN (pin 13) with comments that states that the audio sounds very quite almost not visable, everything is turned up in relation to sounds providing the sound back to the radio but no change at all in the difference with no matter what I tweak,
Is they something that needs to be changed in the rss in order to improve the sound coming back into the radio via the pin or is they a possibility sound could be sent back to the radio via the relevant wire inside the mic itself ???

Thanks again

Do you have a isolation capacitor on the Mic input?

A 2.2 uF capacitor with the + side to the radio's mic input. Most of the time we also use a 2.2K resistor in series with the capacitor in the Mic hi side.