Interface handset to CDM1250

The General forum is where users can discuss any topic regarding Motorola communications equipment - hardware, software, etc. There are also several focused forums on this board, so please take the time to ensure that your questions doesn't fall into one of those categories before posting here!

Moderator: Queue Moderator

Post Reply
LCFD1
Posts: 31
Joined: Tue Mar 30, 2004 8:06 pm

Interface handset to CDM1250

Post by LCFD1 »

I am trying to interface a "telephone style handset" (p/n RLN4756A) to the accessory port of the CDM 1250. The accy port provides floating spkr+ and spkr- pins. As far as I know, the handset has a common ground, mic high, ptt, and handset audio. I have all working except the handset audio.

The reason for connecting it to the accy port is because they still want the conventional mic hooked to the mic jack.

Does anybody have any expierences hooking this up?

Thanks!
-Sonny
User avatar
train_radio_guy
Posts: 263
Joined: Mon Sep 27, 2004 8:47 pm

Handset Connections

Post by train_radio_guy »

Sonny,

You may be able to interface the handset audio through an audio isolation transformer. However, the audio level at the 16 pin accessory jack will directly correspond to the volume control on the radio. If someone were to crank up the volume, the handset audio would become very LOUD, making the handset unusable. You might be better off running the handset from the microphone jack, & connecting the hand-mic through the 16 pin accessory connector. It’s just a thought.

trg :wink:
odat
Posts: 10
Joined: Fri Dec 03, 2004 3:52 pm

Interface handset to CDM1250

Post by odat »

Check out the thread "Second mic for CDM1550" in this forum
If ya ain't the lead dog, the view never changes.
Will
Posts: 6823
Joined: Tue Sep 04, 2001 4:00 pm

Post by Will »

The "receiver" in the handset is fed thru a 1uf cap and a 1K resistor from one side of the radio's speaker line, other side is ground.
Post Reply

Return to “General Motorola Solutions & Legacy Radio Discussion”