Need to add a Mic on an APX7500 O5 Control Head

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nick.dejohn
Posts: 314
Joined: Sun Feb 22, 2004 6:06 pm
What radios do you own?: EX560-XLS CDM1550

Need to add a Mic on an APX7500 O5 Control Head

Post by nick.dejohn »

I have an AXP7500 with the O5 control head and I need to add another mic. Im coming off the back of the control head at the J100 CHUC Mobile Accessory Port. I have Pins 14, 16, and 23 off the back of the control going into a 8-pin telephone style jack box so I can plug a Motorola Mic in and I have nothing. When I key the added mic up I get nothing. Any idea of what I am doing wrong? This shouldn't be that difficult. Its only 3 wires.

Thanks,
Nick
Nick
Jim202
Posts: 3609
Joined: Sun Sep 09, 2001 4:00 pm

Re: Need to add a Mic on an APX7500 O5 Control Head

Post by Jim202 »

nick.dejohn wrote:I have an AXP7500 with the O5 control head and I need to add another mic. Im coming off the back of the control head at the J100 CHUC Mobile Accessory Port. I have Pins 14, 16, and 23 off the back of the control going into a 8-pin telephone style jack box so I can plug a Motorola Mic in and I have nothing. When I key the added mic up I get nothing. Any idea of what I am doing wrong? This shouldn't be that difficult. Its only 3 wires.

Thanks,
Nick



Not sure about the back of the control head, but it does work off the accessory connector on the back of the radio.

I have not done enough programming of the APX radios, so I can't tell you the exact place to go, but on the XTL radios, there was a place that I think was in the advanced section. Near the bottom, was a selection that allowed you to flip flop between the two selections. It should be "AUX PTT AUDIO SOURCE". The two selections are "AUX_MIC" and AUX_TX". If you get the wrong one, you won't have any TX audio. Try it in the default selection. If that doesn't work, select the other one. I run into this all the time working with radio interop installations.

Another point, you might have to go play with the "external mic gain" setting. This again is not the simplest to find in the APX. If your audio is low, you will have to go in and adjust it. The default is the AGC selection. Uncheck the AGC block and raise the "external fixed gain" some.

Don't forget to save the changes to the radio.

Pin 16 is PTT

Pin 23 is TX audio

Pin 14 is audio ground

Jim
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