Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!accuvax.nwu.edu!nucsrl!telecom-request From: Dan Bernstein Newsgroups: comp.dcom.telecom Subject: Re: What Would it Take For Modems to Recognize Call Waiting? Message-ID: <11514@accuvax.nwu.edu> Date: 30 Aug 90 05:57:39 GMT Sender: news@accuvax.nwu.edu Organization: IR Lines: 54 Approved: Telecom@eecs.nwu.edu X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@eecs.nwu.edu X-Telecom-Digest: Volume 10, Issue 607, Message 10 of 11 In article <11160@accuvax.nwu.edu> TELECOM Moderator replies: > [Moderator's Note: Suppose you could set your modem to never time out; > to never drop carrier, meaning you could flash your switchhook to take > a call and your modem would just sit there waiting. If you could do > that, how would the other end know you were on a call-waiting and had > not disconnected abruptly? A timeout is okay. Anyway, I envisioned something like this: Local modem hears call waiting beep. Local modem somehow communicates to remote modem that it's call waiting time. Remote modem acknowledges. Local modem shuts up, dropping carrier. You talk. Eventually the line flashes back to the remote modem. Local modem hears remote's carrier again. Local modem starts generating carrier. Remote hears this and undoes whatever flow control it might have done before. > What you are asking > for is not as easy as merely fixing your own modem to ignore loss of > carrier while you are on another call. Certainly; I don't see this sort of thing working unless both modems are modified to take positive action upon the call waiting beep. Note that once you've gotten over the technical hurdle of recognizing the beep, you can use that for the wait-ack sequence (sort of like a connect). > And if your modem did work that > way, would you want to sit there and try to converse with someone over > the carrier tone (which was still there since you told it not to > leave)? The local carrier would disappear. You wouldn't hear the remote one. > I don't think it would work out at all. On the contrary: all your technical objections are answered by newer phone systems; there's nothing inherently difficult about the idea; and I think most modem users would jump on it in an instant. > And do not think that > the telco is very concerned 'about people getting calls so cheaply', > since most modem owners probably already have a second line to start > with, and a phone bill double what a non-modem user is paying. But a large number don't. Even the ones who do probably wouldn't mind turning one line plus one modem connection into two lines plus one modem connection, for just the cost of call waiting. And as Mark Elkins points out (10/603/10 of 12), the phone company could very well be concerned about this. Dan