Music on Hold - 100 Ohm source when PBX expects 600 Ohm?

What is the connection? Is it 2WEM, 4WEM, POTS? What's the loop length?

If it's a short loop, and you get the levels correct, it shouldn't matter.

Bob

It's just a bog standard headphone connector/cable, the sort you'd plug into a mp3 player etc.

"600ohms" refers to the characteristic impedance of a twisted pair of standard telephony wire at audio frequencies. It doesn't sound like you're interfacing directly with a twisted pair circuit, so its characteristic impedance doesn't apply to what you're doing.

If you can provide some more details then we can help you make the right decision.

Bob

As long as you can set the signal amplitude to what you want, the impedance won't matter much in this application.

Hi,

Thanks. On proprietry PBX and some Open Source ones, they can either serve up music for when a call is on hold from local storage or an external source. Most PBXes can take input sources in the range of

The appliance I am looking at is:

and its audio chip is:

The appliance states an output impedance of 100 Ohm:

But the chip can be set to provide different outputs.

Thanks.

Gavin,

Thanks for the additional info. I'm not sure what your whole hookup is, but if this Pika device is the source for the music-on-hold signal then its output impedance is fine for driving your PBX. Even if the PBX says it takes "input sources in the range of 600-20Kohms", in reality, it will work with a source of ANY output impedance as long as you get the levels correct.

I'd say just hook it up, get the levels right, and then go out and have some fun.

Bob

Will do!

You know, since I started computers late, around 2000 (actually did a degree in Electronics and Communications BEng(Hons) but forgot everything), I got into newsgroups, then I found Open Source and GNU/Linux in 2001. I hadn't been back to a newsgroup since then and always used mailing lists.

I remembered yesterday how *big* usenet was, and wasn't sure about the

Great to see it's exactly the same as I remember it!

Thanks bobw, I'll make sure I subscribe to more and help out others, as is the ethos.

Gavin.

From my experience, PBXs will take just about anything as their MOH source. I used to use cheap tabletop radios, with the amp's speaker output connected directly to the PBX. Your 100 ohm source should be just fine.

This is one situation in telephony where proper impedance matching isn't at all important.

Tom