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From: DREUBEN@eagle.wesleyan.edu (Douglas Scott Reuben)
Newsgroups: comp.dcom.telecom
Subject: CPC / "Wink" Call Termination
Message-ID: <14261@accuvax.nwu.edu>
Date: 3 Nov 90 16:11:39 GMT
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X-Telecom-Digest: Volume 10, Issue 784, Message 5 of 12


Hi-

I'm wondering if anyone here knows exactly (or not so exactly :-) )
what the "wink", or I believe it is sometimes called "CPC" signal is.

I'm referring to the process by which the Central Office switch can
signal a end-user device (an answering machine, for example) that the
calling party has hung up. IE, someone calls my machine, hears the
outgoing message, thinks it is really too long, and just hangs up. The
machine "knows" that the caller has hung up even before it starts
"listening" on the line to see if anyone is recording a message or
not.

I've heard from some sources that this is done with polarity reversal,
and from others that there is just a drop in line current for a brief
momment.  Is either (or both?) correct?

If anyone knows the exact timing (ie, the wink = xxx miliseconds,
etc.) and what voltages are involved, I'd really appreciate hearing
about it. Or, if you'd prefer that I not be so lazy and research it on
my own ( :-) ), could you perhaps steer to the proper sources?? I've
looked in the "Red" Radio Shack book and in my other sources, and have
found nothing dealing with this topic. So just about any info would be
helpful!

Thanks in advance for any/all help!


Doug

dreuben@eagle.wesleyan.edu
dreuben@wesleyan.bitnet

P.S. Gilbert- ( at Rochelle Com. in Texas) - I've lost my entire mail file
     and could use your address again. Could you please e-mail me at the
     above address? Thanks...