telephone switch hold

[angryman]

I know this one is a little out there, but thought I'd try...at my company, we have a stand alone cd player that is used for music for people on hold. It is (was before I got here and no one here knows, etc..) wired from the headphone jack into 2 wires on the connector strip (the switch?) but nobody knows what they are....anyways, there is a lot of static on the music (on the callers phone) on the outside line. It's definately the connection to the switch and I am just curious what those 2 wires may be going to concerning the phone system. Also, I was thinking a small cap between the 2 wires may clean up the noise, or is that just a stupid thought?

Any comments are appreciated...

Thanks,
Mark

 

[OperaHouse]

If I remember corectly, a hold is caused when a 10K resistance load is placed on the line. I would suggest an isolation transformer between the CD player and the phone line. There may be a ground problem between these items or the output cap may be breaking down because of the higher or reversed voltage on 1t. You might start by using a non polarized 1uF at at least 100V to couple the signal. Next try a 10K to 10K audio isolation transformer. The 1uF may still have to be used on the line side.