XPR4550 Audio Issue

[Vercomm]

Hey Gang,

I have encountered a strange issue with an XPR4550. We are running the radio in analogue only and the unit does have the newest firmware 1.6.20.

We have a device sending audio into the xpr through the rear 26pin connector. The audio is voice band and also paging tones.

This is the scenario, paging tones are sent and voice follows (very simple). 1 out of 8 times the paging tones are not being transmitted, but the voice is always transmitted. And of course our radios are set to AND unmuting which menas we need the paging tones to unmute. I have checked the device that generates the paging tones and audio and it is working 100%, never misses a beat. The deviation of the XPR is bang on (when the tones work).

In the CPS, the analogue and digital mic AGC are enabled as well as talk permit tones.........those were the two things that came to mind right off the top of my head.

I should also mention we have our audio generating device connected in the same scenario to CDM1250's and we have 0 problems with those setup's.

The external device is an NXU.

Any ideas, things to check, thoughts, hunches. This is for ambulance dispatch so i need to come up with some answers........thanks guys!!

[chartofmaryland]

Try turning the output audio down from the NXU to the XPR. If the voice is at a certain level and the tones are at another then the tones will be clipped and the audio will make it through. You will hear both every time if after turning down the audio tone and voice are heard.

If this doesn't work then there is a audio filtering problem with the XPR that may be due to the DSP that is not present in the CDM.

The latter is a bit of a stretch so check the audio first.

CoM