Thanks to http://www.porticus.org/, I've actually learned where to look on the keypad for the part number and the manufacturing date (which may help identify which one is from a phone and which one is 35Y3D / Apr 1977 - 7 wires as previously described 35AF4A / Jan 1081 - 11 wires as previously described Here's a close-up shot of the one... http://www.porticus.org/bell/images/dial_35y3a.jpg ... and the schematic... http://www.porticus.org/bell/images/35_dial.gif ... from which I can deduce that I should have *8* wires. Close examination of this dial shows an off-board connector that is totally missing a wire, so that must be where "blue" goes, and the green wire next to it is weakened from flexing and about to fall off, too. It's an unfortunate circumstance of the board attachment points being right at the opening in the plastic shell with nothing to prevent them from moving combined with the engineering expectation that these wires are going to be sitting in a phone and not subject to much stress. So... now I know I have a 35Y3D and a 35AF4A and have a 35Y3D schematic. The next step is to find any docs that relate to the modem-equipped ASR-33 and where the dial attaches. -ethan

On Sat, May 16, 2009 at 8:26 PM, Fred Cisin <cisin at xenosoft.com> wrote: Yes... but fingers weren't as fat then (should be 1981, of course). More digging... Found a schematic for the 35AF4A on http://www.telephonecollectors.org and a text table with the following entry... "Substitute for 35C3A dial. Not for general purpose type telphone sets. Intended for use in 2565GK, HK, LK, 2568HU, HAA, and 2580A telephone sets and 1035AF3A adjunct dial." This is now pointing me strongly in the direction that the 35AF4A is the one I'm looking for. Now to find docs on the "network" in the ASR-33 for what color wire goes where. -ethan

Yes, it's pretty clever... THis is mildly OT, but does anyone know of a source of the schematic for the computer-interfaced autodialler (is that a model 108???) with an RS336 interface from about that time? Finding the actual unit would be even better, but I suspect that's impossible over here. -tony

On 18 May 2009 at 12:28, Dave McGuire wrote: Varistors. Telco stuff was usually silicon-carbide rather than metal oxide. Although they were used for circuit protection, and amplitude- limiting (look inside the receiver of any 2500 series desk set), they were also used for circuit stabilization, which is, I think, the application in the dial circuit. --Chuck

On 18 May 2009 at 16:17, Dave McGuire wrote: What's noteworthy is the stability of the thing. ISTR that DTMF signalling relies on a tolerance of something like +/-2%. A mass- produced LC oscillator that operates reliably close to tolerances in a steel mill or a meat-packing plant is a marvel. --Chuck

On May 18, 2009, at 6:07 PM, Doug Jackson wrote: If they don't like Veroboard, they don't like electronics. -Dave -- Dave McGuire Port Charlotte, FL

Richard wrote: Tis true, but in the early 80's it simply cost too much, at least to those of us working in budget constrained universities.

Thanks for that Richard, Obviously my memory was wrong. Here in Australia, we definitely were not using it in 1984 at the Australian National University :-)

Chuck Guzis wrote: Here's a schematic of an Automatic Electric phone, the circuit a little more recognisable as a simple emitter-follower oscillator with dual resonant circuits: http://www3.telus.net/~bhilpert/tmp/AETTphone.gif The resonant circuits are in parallel in this version rather than series. (Note the 2% tolerance caps.)

On May 18, 2009, at 5:04 PM, Chuck Guzis wrote: Wow. That's pretty damn impressive. -Dave -- Dave McGuire Port Charlotte, FL

On Tue, May 19, 2009 at 3:56 PM, Tony Duell <ard at p850ug1.demon.co.uk> wrote: Given that the switch to IC-based tone generators looks to be around 1982, before the breakup of Ma Bell, I'd say that there are few phones in thrift stores here of that vintage any more. Maybe at an estate sale from someone who hasn't moved in 25 years. If you have access to lift the faceplate, look for a part number starting in '35' and a manufacturing date prior to 1982. You don't want a part number starting with '72'.* -ethan

On Wed, May 20, 2009 at 2:47 PM, Tony Duell <ard at p850ug1.demon.co.uk> wrote: I couldn't say for certain, but even into the 1990s, the phone company charged $1-$2USD/month for TouchTone service. Mostly by then, it was just a surcharge applied to your bill for their convenience. When I got a data line for UUCP around 1990 or so, I told them "no extras" - no call-waiting, no three-way-calling, no speed-dial, and no TouchTone. They tried to persuade me to get their profit-laden features, but they really balked at setting me up a pulse-dial line. I suggested that if it wasn't an option that could be canceled, then perhaps they were exceeding the rates set by agreement with the Public Utilities Commission. They acquiesced. I did have to patch the UUCP dialer program (I was calling from an Amiga and didn't have the right compiler environment to build from source) because you could _not_ pick pulse dial from L.sys because the app had "ATDT" hard-coded. A quick change to ATDP and it was happy. I learned on my first visit that in the UK, a hundred miles is a long way, but in the US, a hundred years is a long time *(I stayed in the "New Buildings" at New College - "new" because they were built by Queen Victoria and dedicated, like so many things, to Albert's memory. A building that age at home would be nearly as old as the State I'm from). For us, "antique" has a substantially smaller scale than for you. OTOH, I've driven over 1,000 miles in a weekend (closer to 1,200 miles), to buy a PDP-8/S, FWIW. Here's another datapoint on the timescale difference - when was at Oxford in the 1980s, we were told that "current events" (as opposed to "history") encompassed pretty much anything more recent than the death of Queen Victoria (i.e., about 75 years or so). At home, at the same time, "current events" encompassed anything since the end of the Vietnam War (around 10 years or so). Anecdotally, I'd estimate the interpretation of the phrase "not that old" to be around 6:1 to 10:1 if spoken by someone from the UK compared to spoken by someone from most of the US (allowing for regional variation in New England, being the older part of the US). I am not joking in the slightest. I'm not suggesting you try this without the cooperation/permission of the seller, but you can either pop the faceplate out the front (and with a wee flat-blade screwdriver on the clip at the top, pop it back in), or just loosen the two screws and unmate the base from the top. The date is easily visible as a NN-MM month and year number, and the part number is in the same color paint and visible from the same orientation (near the buttons on the face of the dial). There might also be a stamped manufacturing date on the bottom, but I couldn't give you any specific guidance about format. If it's an ITT or other non-Western Electric phone, I'd wager it's IC-based. AFAIK, only the W-E phones (i.e., pre-breakup) would have the 1-transistor-2-coil keypad. -ethan

Ethan Dicks wrote: As indicated in my previous message on the topic, Automatic Electric was producing a 1-transistor DTMF design in the 60/70's, almost identical to WE's. -- I don't know what it was like in the Bell/WE regions, but out here DTMF, while available, didn't really take off until sometime in the late 70's/80's I would say, perhaps in correlation with the switch to IC-based DTMF. I'm guessing the number of 1-transistor DTMF phones produced was relatively small, (particularly) compared to the number of dial phones produced in the same time period.

On 20 May 2009 at 18:54, Ethan Dicks wrote: For many years they made the phone equipment for GTE. Later, they were known as GTE Automatic Electric, founded by one Almon B. Strowger (he of the Strowger switch). Whatever's left of it is probably owned by Lucent. I used to have an AM (germanium) transistor radio made by them. Steel chassis, transistors in sockets. Sadly, it was lost in an accident. --Chuck

On 20 May 2009 at 17:16, Brent Hilpert wrote: The GTE saga is quite interesting. I recall during the 70's listening to Chicago Symphony rebroadcasts from WFMT in Chicago, where GTE was one of the sponsors. Since WFMT standards prohibited pre-recorded commercials (they were always read by an announcer), they had to be a bit more interesting than the usual noisy garbage served up on radio. The GTE spot would typically highlight one of the GTE companies, such as Automatic Electric, Sylvania, Philco or Lenkurt and describe their products. "Gee--no, GTE!" Now, GTE seems to be as forgotten as "The Bell Telephone Hour". Back then, most of the communities in Silicon Valley were served by Pacific (Bell) Telephone, with the exception of Los Gatos, which was a GTE outpost. I don't know what the inter-network interface was, but it must have been something along the lines of acoustic couplers, because the quality of a call to Los Gatos was execrable. A 300 bps modem connection was difficult to say the least. --Chuck

As an aside, some of the earlier pushbutton 'phones in the UK (which were rensted from the Post Office) used loop disconnect (pulse) dialing. The dialer unit had a PCB with 3 or 4 metal-can (TO99 or similar) ICs on it, which I never managed to indentify. They may well have been custom. My point is that IIRC an 'antique' has to be over 100 years old. Sounds like you were at what I call 'The Other Place' :-) Sure... This reminds me of a story when I was at Cambridge. An obnoxious American tourist (no, not all Americans, or all American tourists are obnoxious, but this one was) asked the porter at one of the older colleges 'Is the college pre-war'. The porter replied 'Sir, this college is pre-America' :-). Yes, of me, going 100 miles (each way) to pick up a classic computer is a long trip. Except at radio rallies, I have naver had permission to take something apart before buying it. Maybe remove clip-on covers, but using tools is a no-no. I can understand why -- the seller doesn't know that I have this way of gettign things back togther. Equally I don't know that the case ising internally cracked and will fall apart when I take out a screw. Right. So, alas, the chances of me finding one over here are pretty remote :-( -tony