Batboard

I have a XTS5000 here at work that I'm trying to interface with an vehicle intercom system. I have the pinout from the XTS5000 and have the intercom interfacing with the radio in every aspect but the TX audio. The audio being transmitted is muffled and very low. Does anyone have any specs on what the impedance is on the TX audio from the side connector of a XTS5000 radio?

XTS or XTL 5000?

Can't say I have heard of a portable interfaced to an intercom system, but I guess anything is possible.

The input Z on the external MIC input is 2.2K ohms.

What type of mic element and biasing is on your intercom ?

The reason I ask is because the tx audio on the XTS UDC supplies a DC bias for the external speaker mics electret element and if your intercoms tx audio has its own bias for its mic then you will need to capacitively couple the intercoms tx audio going to the XTS TX audio on the UDC.

As I mentioned, If the intercoms mic is self biased, by this I mean that it is not supplied from the radios UDC connector, then couple the tx audio from the intercom to the XTS UDC using a .22 to 1 uf non polarized, ceramic capacitor.

Also you can try setting the CPS> RADIO WIDE, TX AUDIO CONTROL PER MODE (analog digital or secure), EXTERNAL MIC GAIN TO AROUND +6 to +9 and see if it improves the audio level.

You should adjust the above mentioned TX AUDIO gain CONTROL setting to balance the levels between the internal and external mics.

I run an external home brew 900 MHz wireless mic and I Find that the above external mic gain setting and respective coupling capacitor range works fine for me.


Mike

Nope, it is indeed an XTS 5000. Thanks Mike for the reply, I'll try the mic gain settings and let you know how/if it worked. It sounds like a simple enough place to start. Not sure on the mic element on the intercom. I don't have any specs on the intercom system and I'm not getting a lot of help from the intercom manufacturer. And the reason for interfacing the portables is that our department decided to save some money and only by portable radios. No mobiles installed here! It makes it really difficult for the guys to here in the rigs plus it makes it difficult to communicate because everyone has to have their radio on to hear. So when the officer has to communicate with dispatch, he's getting the echo effect from everyone else’s' radio in the cab. We had our intercoms interfaced with mobile radios on our old VHF system, so I thought I would experiment and try and find a solution.

I have to agree with Mike, that the XTS radio mic bias is causing some of the issue. If you are connecting from
an audio source that might be shorting this bias out, it will also cause the low audio and muffled sound in TX.

You should try the series cap in the hot mic wire to eliminate this problem.

Jim

n9upw wrote:I have a XTS5000 here at work that I'm trying to interface with an vehicle intercom system. I have the pinout from the XTS5000 and have the intercom interfacing with the radio in every aspect but the TX audio. The audio being transmitted is muffled and very low. Does anyone have any specs on what the impedance is on the TX audio from the side connector of a XTS5000 radio?