Batboard

Does the flat audio out (pin 11 and 7) of the cdm1250 mobile provide balanced or unbalanced 600 ohm audio audio?

I know it is a stupid question, but I failed basic electronics in high school, thanks, Rob

Unbalanced. The other portion of the audio path for pin 11 is carried on the chasis ground (pin 7). A balanced output, like the audio PA for the external speaker, will be carried on two signal lines, each 180 degrees out of phase with each other, and not referenced to the chasis ground.

HumHead wrote: and not referenced to the chasis ground.

True.....sometimes. If a transformer feeds the line and the line side has a CT or split winding with the center tied to ground, it's balanced to ground. If there's no CT or ground connection to the line side winding, it's just balanced.

So this audio is 600 ohm unbalanced. Thanks, Rob

I don't think it is 600 ohms, more like 1000 ohms. And, yes, unbalanced.

You do not want to load down the output on the CDM or the audio will be distorted.

Rob, What are you 'driving' or have hooked to the CDM?

I am trying to hook up a cimmaraon decoder to the output of the CDM, but my decode rate is not 100%. This is obviously for a base station install. Thanks, Rob

It is noteworty to mention that a ITA2000 tone remote is also hoked up to the radios, so I tapped off of pins 7 and 11.

Thanks, Rob

Read the Cimarron manual, which is quite complete.

You should jumper the decoder for unbalanced, hi-Z. Then set one -- and only one -- of the jumpers for attenuation.

I have a stableful of C Plus IIIs working, and they are excellent devices.