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From: jon_sree@world.std.com (Jon Sreekanth)
Newsgroups: comp.dcom.telecom
Subject: Re: Unbreakable Dialtone
Message-ID: <16312@accuvax.nwu.edu>
Date: 22 Jan 91 15:16:43 GMT
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X-Telecom-Digest: Volume 11, Issue 58, Message 3 of 13


In article <16253@accuvax.nwu.edu> TELECOM Moderater noted:

> would work correctly. One of the improvements in telephony in recent
> years is the ability of telco to deny tone service to people not
  ....
> only an occassional failure, it is probably because the CO is now and
> then sending you the 'wrong' dial tone. Try to explain to the Repair
> Bureau that on occassion you 'cannot cut the dial tone' and ask if
> they are from time to time sending you a dial tone intended for rotary

I'm not looking for 'dangerous hacker information', but are you saying
that the dial tone contains some encoded information ? That is, other
than the 350 - 440Hz pair, are there some other signals, or
frequencies out there in the dial tone? (I ask because my designs use
standard assumptions to detect on/off hook, dial tone, ringing, CPC,
etc.)

Thanks, 

Jon Sreekanth

Assabet Valley Microsystems			Fax and PC products
346 Lincoln St #722, Marlboro, MA 01752		508-562-0722
jon_sree@world.std.com


[Moderator's Note: My phraseology was not the best in that message.
I'll let Dave Levenson clarify it in the next message.   PAT]