Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!mailrus!accuvax.nwu.edu!nucsrl!telecom-request From: cellar!martin@bellcore.bellcore.com (Martin Harriss) Newsgroups: comp.dcom.telecom Subject: Re: Touchtone History Message-ID: <9617@accuvax.nwu.edu> Date: 11 Jul 90 15:32:56 GMT Sender: news@accuvax.nwu.edu Reply-To: Martin Harriss Organization: Bellcore Lines: 34 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 475, Message 6 of 9 In article <9570@accuvax.nwu.edu> clive@ixi-limited.co.uk (Clive Feather) writes: >The UK had push-button pulse dial phones for a *long* time before >DTMF signalling arrived. >Anyone remember the Trimphone ? Unfortunately, I do. They were horrid things. The Trimphone was the PO's attempt to give customers something other than the run of the mill 700 type telephone. Trimphones did, in fact, have rotary dials when they were first introduced, sometime in the late 60's. It was sometime later when the push button pulse dial models came out. We had a trimphone put in when we moved in '68. In those days the PO owned the phones. It had a "modern" look and the dial was luminous so you could find it in the dark. The main problem was that the mic was stuck up near the top of the handset. You spoke into the mouthpiece, and your voice travelled up the inside of the handset to the mic. Having your voice sent up a hollow tube in this fashion was probably not good, but even worse was the fact that in this particular orientation the carbon granules(!) in the mic would stick in a particular way that made it sound like you had a perpetual cold. Banging the handset periodically would help, but not for long. When we eventually figured out what was wrong, we had the unit swapped for a new one, and it was ok for a while. I found that the mic in the new unit was quite sensitive at 2280Hz. Martin Harriss martin@cellar.bae.bellcore.com