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CPC / Disconnect Clear

CPC / Disconnect Clear

CPC / Disconnect Clear

(OP)
Hi,

Sometimes I have to install Panasonics (TEA308 and 824) on analogue lines.  Often part of the requirement is fax detect...

Sure, with a bit of jiggery pokery, this all works (ish). In order to prevent phantom calls (i.e. caller hangs up before answer and phones will continue to ring until answered) I request that the line provider implement disconnect clear (loop current drop) on the lines (usually duration of 500mS).  In order to make this work with the panasonics I have to set the CPC to, typically, 46mS (about 10% of the provider set value) to get reliable disconnect.  On other PABXs (IP Office) I get reliable results by using about 150mS less than the provider's value.

Why is this?  Have I misunderstood how CPC works?   Any clues?

Take Care

Matt
I have always wished that my computer would be as easy to use as my telephone.
My wish has come true. I no longer know how to use my telephone.

RE: CPC / Disconnect Clear

I didn't think you's had cpc at all in bt land...
and its not a current drop over hear  its an current
reversal!

RE: CPC / Disconnect Clear

(OP)
>I didn't think you's had cpc at all in bt land...

Maybe we don't...

> and its not a current drop over hear  its an current
reversal!

That might be why it performs differently to how I expect.  However there is a marked difference between CPC not set and set and that difference achieves may aim.

So does CPC expect a reversal and,in reality, only detect the "edge" transition (hi->low or low -> hi) and that is why it woks for me?  

Take Care

Matt
I have always wished that my computer would be as easy to use as my telephone.
My wish has come true. I no longer know how to use my telephone.

RE: CPC / Disconnect Clear

don't rightly know I've been there, have famly
there but have not installed any equipment on that side of the pond....

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