Batboard

our department has gone to Knox Sentralok key locks. We currently utilize CDM1250 radios in the apparatus. in order to integrate the key boxes to be released by the dispatcher I need the tones that come over the radio channel to be transferred over to the Sentralok box.

I figured that the "flat audio" on pin 11 of the accessory plug was the best way to go for this, but it's a 2 wire setup from the sentralok box, where would the other audio wire be connected ?

I suppose the other option would be to use the "speaker" pins, but I fear that if someone turned the radio down too far or up to far that the signal would not be able to be picked up, or it would become too distorted respectively.

Any guidance would be appreciated

I know that my department uses the flat audio for the Knox box keys. Not a problem - CDM 1250's & 1550's

I would ask someone better versed, than myself, on accessory pins - I am not sure what you would use with the flat audio (I would think another flat audio or an audio ground). I'm sure that someone here can give you the correct info.

One wire to flat audio out, the other to a ground pin. Pin 7 will work

Pin 7 is ground
Pin 11 is flat rx audio and is partially programmable
Pin 1 is speaker -
Pin 16 is speaker +

The flat rx audio should work

One point that you should investigate is that there is some DC bias voltage on the pin 11 flat audio out.
Check out the internal circuit of the Knox Box and see if they have a cap in series with the audio input.
If not, then you might want to add something like a 1.0 uf cap to block the DC.

I have seen some installs where if the cap was not installed, the fixed audio level was too low to be used.
Without the cap, the signal gets grounded by what ever the load is that you are connecting.

Jim

fineshot1 wrote:Pin 7 is ground
Pin 11 is flat rx audio and is partially programmable
Pin 1 is speaker -
Pin 16 is speaker +

The flat rx audio should work

I have a mobil repeater connected to a CDM 1250. It uses the Discriminater , pin # 11, can I also connect the Sentraloc to the same pin without causing any loading problems. Thanks.

JD wrote:I have a mobil repeater connected to a CDM 1250. It uses the Discriminater , pin # 11, can I also connect the Sentraloc to the same pin without causing any loading problems. Thanks.

Without having schematics in front of me of all equipment used, I would expect loading when double terminating like that. You should probably make a resistor bridge to minimize the effect, and then adjust your inputs accordingly.

I think you would want the FILTERED AUDIO output.

"Mobile repeater" ? Can you elaborate?

Pyramid SVR 200 ,