davidb@pacer.uucp (David Barts) (03/10/91)
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 ;-).
crocker@uunet.uu.net (Ronald T. Crocker) (03/12/91)
Not being an expert on the subject, I seem to recall that MTS or IMTS phones were rotary dial, and that they did, in fact, use some kind of pulse dialing scheme. Can anyone with (any? more?) information follow up on this. Ron Crocker Motorola Radio-Telephone Systems Group, Cellular Infrastructure Group (708) 632-4752 [FAX: (708) 632-4430] crocker@mot.com or uunet!motcid!crocker
JTUCKER@vax2.cstp.umkc.edu (03/15/91)
Is it possible to take a phone that only has pulse dialing and convert it to tone dialing? Joseph Tucker [Moderator's Note: Well, sure it is. You would open the phone, disconect the dial and associated wires, yank it out and insert a touch tone pad there instead. Of course, the shell would not fit correctly since the cut out on the rotary dial phone is round, and the cut out you'll be needing is square. Why bother, given the inexpensive and high quality touchtone phones on the market? I could walk from home to the Radio Shack, buy a phone and bring it back quicker than I could modify an old dial phone. PAT]
john@zygot.ati.com (John Higdon) (03/16/91)
"Ronald T. Crocker" <motcid!crocker@uunet.uu.net> writes: > Not being an expert on the subject, I seem to recall that MTS or IMTS > phones were rotary dial, and that they did, in fact, use some kind of > pulse dialing scheme. Yes, they did. All number transmission was "rotary" based on IMTS. When you would come "off hook" on your mobile unit, it would look for an idle channel that was in operation. With IMTS, there were not many. When the mobile found a channel with idle tone, it would key up and identify itself by "dialing" its assigned phone number for the base system. Dialing consisted of a tone that was frequency shifted once for each pulse. It sounded like a series of "tweedles". If your mobile number was valid, the system would return dial tone. Your call was placed using the rotary dial provided. However, instead of using hard wire to send DC pulses, it used that frequency shifted tone. The dial would come off home and the tone would begin. As the dial returned, each pulse would be represented by a shift in the tone's frequency. A person monitoring the line could easily determine the dialed number. For the record, there was another way calls could be rotary dialed without hard wire. Many LD tandems used to respond to pulses of 2600 Hz and would complete calls based on numbers "dialed" in this manner. Hence, 2600 Hz would serve as both supervisory and signaling carrier. It was called "SF" (single frequency). John Higdon | P. O. Box 7648 | +1 408 723 1395 john@zygot.ati.com | San Jose, CA 95150 | M o o !
briang@eng.sun.com (Brian Gordon) (03/17/91)
In article <telecom11.205.4@eecs.nwu.edu> JTUCKER@vax2.cstp.umkc.edu writes: > Is it possible to take a phone that only has pulse dialing and convert > it to tone dialing? > [Moderator's Note: Well, sure it is. You would open the phone, > disconect the dial and associated wires, yank it out and insert a > touch tone pad there instead. Of course, the shell would not fit > correctly since the cut out on the rotary dial phone is round, and the > cut out you'll be needing is square. Why bother, given the inexpensive > and high quality touchtone phones on the market? I could walk from > home to the Radio Shack, buy a phone and bring it back quicker than I > could modify an old dial phone. PAT] Gee, I'm less imaginative. I'd just replace the mouthpiece with one of those "touch tone mouthpiece" devices and just ignore the original dial. Brian G. Gordon briang@Sun.COM (if you trust exotic mailers) ...!sun!briangordon (if you route it yourself) [Moderator's Note: What I particularly dislike about those tone pad in the mouthpiece devices is how easily they seem to get the buttons stuck and gummed up. If you hold the receiver on your shoulder with your head cocked to one side it is easy to get saliva sprayed on the pad as you are talking. If you rely more on what you hear in your ear rather than what you see your fingers doing when dialing (to insure you have dialed corectly) then you have a more difficult time. Maybe some of those things are well built and sturdy, but I have yet to see one in use after a couple months that was not nasty from the close proximity to the mouths of everyone who had eaten/smoked cigarettes while talking on the phone, plus having buttons that were starting to get stuck. I'd not think of those things as a real conversion. PAT]
bruce@camb.com (Barton F. Bruce) (03/17/91)
In article <telecom11.205.4@eecs.nwu.edu> JTUCKER@vax2.cstp.umkc.edu writes: > Is it possible to take a phone that only has pulse dialing and convert > it to tone dialing? Sure, but hardly worth it. When TT was still young, and most phones were rotary 500 sets, there were kits that would do it. They came in two flavors. One had a round plastic insert that was punched for the TT buttons that would fill the old rotary dial whole, and the other would have a whole new housing. You got to reuse most everything else. Later there were versions that were even notched for the modular jacks you were likely to want add with the new housing. Back then places like North Supply often stocked phones less ringers because whatever tuned party line ringer that was needed would be added in the field. Also back then it was still illegal use your own phones. Not having a ringer meant the test desk couldn't count it. A ringerless 500 set was $11, and a TT 2500 was $28. The versions with a straight line ringer were about $4 more. A replacement TT pad by itself was $23. The kit to convert a 500 to a 2500 was only peanuts less than the whole 2500 set. The dial brackets for a rotary dial go straight up inside, while for a TT pad they offset in towards the center a bit as the TT pad is narrower. The rebuild kits included little spacers to allow the TT pad to mount in a rotary dial phone. They also included an auxiliary terminal strip for the extra connections the earlier transmission networks wouldn't have screws for. Eventually electronic TT pads got down to maybe $10, and got static proofed so they were reliable. Kits would then have been cheaper, but so were complete phones. An imported 2500 set with an extra jack for hotel guests to plug their modem into and a message waiting light in ever pleasing ASH color, and by the case of eight may cost between $20 and $25 each during the regular 'specials'. You can even find much cheaper ones, but you may wish you hadn't. As you leave a NY subway, you may be able to buy one for less than $5, but you definitely get what you pay for.