So yeah, after a 16 hour round trip last year to acquire a Teletype ASR-33 that has since been patiently waiting for me to drum up the courage to disassemble and fix the keyboard, I recently acquired ASR-33 #2, however although this one is more or less an ASR-33, its branded as an Anderson Jacobson ADT-233, and has an interesting feature…
This particular model has a built-in acoustic coupler, made by Anderson Jacobson, who were known for acoustic couplers and modems. I suspect internally it may be similar to their DC–230 model, however this is completely contained in the UCC area, and has no external boxes in the base, at least nothing factory anyway.
If you’re unfamiliar with them, acoustic couplers were how you would connect a terminal or computer to a phone line back in the day. The idea was from pre-Carterfone times where Ma-bell dictated that you couldn’t connect anything but ma-bell-owned equipment to a phone line. Instead you plopped the receiver of your phone into these rubber cups, and the modem in the coupler simply talked the same way you did – using the receiver! See below for an awesome video on how these work, and likely identical to how this one would work as well.
For now I’m just going through this one to see what it needs, as I need to order some oil in order to do maintenance and lubrication on both of these machines. I’m also removing some added on modifications to try to bring it back to factory config.
One of those modifications was this thing, which appears to be a current loop to RS – 232 adapter. This thing is fairly crusty and doesn’t have much protection, so it will be removed. This may be based on or similar to this one.
(Note - Jeff's ASR-33 wiki page is an awesome ASR-33 "getting started" resource. Also search for Bill Degnan and ASR-33; he has some presentations and other threads on ASR-33 restoration and repair.)
Circling back, the coupler seems to be just a special version of their off-the-shelf acoustic coupler. Its built on top of the Teletype UCC-6, which is the standard “computer” interface.
In order to make room for the coupler board, the SMD driver board has been turned around to face inward. As such, a board known for getting pretty toasty now gets even hotter, having been enclosed in a metal box. (The coupler is “open” in the picture.) The SMD board in this one is the 60ma version and appears to be original. You have to remove the coupler board to get the SMD board out.
That switch you see that looks like it’s taped on I believe may have been the power switch for the RS-232 adapter. I may leave the switch in place as there is a hole for it in the top cover, but not sure if it’ll do anything. There was another switch dangling underneath (you can see the thin brown wires going everywhere), that switched bit-5 of the data bus, so it was likely a DIY “caps lock” switch. That will be removed as well as its just dangling and the wiring is fairly sketchy.
As you can see, this thing is pretty filthy and needs a good cleaning. Unbeknownst to me, the chad box underneath was nearly 100% full! I gave it a once over and fired it up; so far it’s showing signs of life; the motor is free and runs great, and it decodes and prints from paper tape. That said some parts are very gummed up, including the keyboard. The coupler is NOT showing any signs of life (no lights, and didn’t respond to a 300 baud carrier), and I suspect it may have been disconnected when the RS-232 mod was added. I did notice this connector hanging free in the UCC area, so Ill be investigating that.
While I’m sure others are around, I think this machine may be fairly rare, as I’ve only seen a couple mentions of it in doing some searches. I would love to find documentation for this specific model, as I can’t seem to find anything beyond some advertisements. The only documentation specific to this would really be for the coupler; a schematic and wiring diagram would be nice. Everything else appears to be factory ASR-33 and UCC-6.
If you have any information or documentation, please leave a comment below.