Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!accuvax.nwu.edu!nucsrl!telecom-request From: Dan Bernstein Newsgroups: comp.dcom.telecom Subject: What Would it Take For Modems to Recognize Call Waiting? Message-ID: <11160@accuvax.nwu.edu> Date: 21 Aug 90 14:33:07 GMT Sender: news@accuvax.nwu.edu Organization: IR Lines: 41 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 585, Message 6 of 14 In this city, a local phone call of unlimited length has fixed cost. Call waiting is a lot cheaper than an extra line. It occurs to me that modems could reasonably recognize the call waiting beep. Then the user could answer the call and talk normally, without dropping the computer connection. In other words, for a monthly call waiting charge, you could get a permanent, basically free connection to the computer of your choice. What would it take to get this working in practice? The modem technology would be relatively simple: the hardest part would be convincing the modem on the other side not to hang up during a regular phone conversation. (It shouldn't be hard to make this work with answering machines either.) But what would the phone companies think of people getting connections so cheaply? Dan [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 abrubtly? What would prevent the other end from dropping carrier after it found your carrier was lost? Now if the one on the other end was fixed like yours, to ignore loss of carrier and just sit there humming away waiting for someone to return, then what would happen if some other user called and got accidentally cut off? How would the distant modem recover from that? 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. 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)? I don't think it would work out at all. 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. PAT]