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Path: utzoo!watmath!clyde!burl!ulysses!harpo!decvax!mcvax!piet
From: piet@mcvax.UUCP (Piet Beertema)
Newsgroups: net.dcom
Subject: Re: UUUUUUUUUUUUUUUUUUUU -- maybe an answer?
Message-ID: <5809@mcvax.UUCP>
Date: Thu, 17-May-84 14:09:04 EDT
Article-I.D.: mcvax.5809
Posted: Thu May 17 14:09:04 1984
Date-Received: Fri, 18-May-84 06:15:21 EDT
References: <4644@amd70.UUCP> <485@decvax.UUCP>
Organization: CWI, Amsterdam
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<>

	>....a once-per-second garbage character, regular as clockwork.
	>....the transmission-line hardware "steals" an 8-bit datum
	>for resyncronization.
I don't think that's the explanation. At least on international (and
maybe too on cross-country) lines a very low pitched note is used for
pulse (tick) counting for connect duration timing. The interval between
ticks depends on the distance over which the call is made. 
But an ordinary telephone set can't reproduce such low notes. The
only way to hear it is by "tapping" (via a coil) the phone line and
reproducing the sound via a Hifi amp. You may ever have noticed it when
listening to some direct phone talk on TV (at least in most European
countries, where the TV sound is transmitted via FM) or to the (FM!) radio.