Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!sdd.hp.com!uakari.primate.wisc.edu!zaphod.mps.ohio-state.edu!casbah.acns.nwu.edu!nucsrl!telecom-request From: davidb@pacer.uucp (David Barts) Newsgroups: comp.dcom.telecom Subject: Rotary Dial w/o Wire Connection Message-ID: Date: 10 Mar 91 08:46:50 GMT Sender: news@casbah.acns.nwu.edu (Mr. News) Organization: TELECOM Digest Lines: 29 Approved: Telecom@eecs.nwu.edu X-Telecom-Digest: Volume 11, Issue 191, Message 9 of 11 Originator: telecom@delta.eecs.nwu.edu X-Submissions-To: telecom@eecs.nwu.edu Nntp-Posting-Host: hub.eecs.nwu.edu X-Administrivia-To: telecom-request@eecs.nwu.edu The Moderator writes: > [Moderator's Note: Rotary dial will NOT work on cellular phones, since > there is no loop of wire to be opened and closed by the pulsing. In > any situation where there is not a direct hardwired link to a central > office switch, i.e. cellular, then rotary is not a valid service. PAT] A more accurate statement is "In any situation where there is not a direct hardwired link to the CO switch, *pulse* is not a valid service." I have actually used an old amateur radio autopatch that worked with rotary (yes, rotary) dialers. The rotary dialer encoded a make/break as a 1200/1800 Hz (I think these were the tones; my memory's a little fuzzy) tone. The "break" tone would start as soon as I moved the dial from its rest position. This gave dialled digits a "deeeeeee-doodle-oodle-oodle-oodle" sound. Tone detectors controlled a relay on the autopatch that interrupted the phone line when ever a "make" tone was heard, thereby dialling the number. This arrangement was common back in the 1960s. One thing to note is that while encoding rotary digits as a pair of make/break tones was widespread, the frequencies themselves were not. Basically each repeater (or region) picked its own pair. Unless you got lucky, your dialer (for your club's autopatch) was useless in a strange city. As far as rotary service not being available on cellular, no disagreement there ;-).