Off-topic informational anti-spam anecdotal

From: Russ Blakeman <>
Date: Thu Jul 16 07:30:17 1998

Allison J Parent wrote:

> <If the caller ID data signal was sent first, it would cause jittering in
> < mechanical ringers, and a maddening noise in electronic ones. When the
> < ring is detected, the caller ID can 'pick up' the phone line briefly to
> < check the data signal, which should be extremely brief. The station
> < knows to keep ringing the phone if the user has caller ID. This is my
> Wrong.
> Caller id senses the ring and does not go off hook as that would disturb
> the CO and it is uneeded. Instead the ring is an alert to the caller ID
> that data will follow and it's already camped on the line using a non-DC
> (capacitor coupled) connection to avoid loading the line. this allows
> it to hear the ring and the data.

The caller id info rides as a carrier on the line too at a different
frequency than the voice signal so that only the id box (and similar
instruments) can read it. If I'm not mistaken it's sent as a 300 baud
carrier. The way it senses the ring is the increase in DC line voltage from
an average 35vdc to around 80vdc, telling itself to look for and recieve a
data string which includes time and date.

 Russ Blakeman
     RB Custom Services / Rt. 1 Box 62E / Harned, KY USA 40144
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Received on Thu Jul 16 1998 - 07:30:17 BST

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