Standard Models: 33-ASR, 33-KSR, and 33-RO
The Teletype Corp Model 33 was offered in Receive-Only (RO),
Keyboard-Send-Receive (KSR), and Auto-Send-Receive (ASR) versions.
The M33 is a ...
This is my Western-Union-branded M33-ASR TWX machine. This one has a touch-tone
dialer, but TWX machines also came with rotary dialers. Also having rotary dialers
are the similar-looking Telex machines, which can be identified by four pushbuttons
below the dialer, whereas the TWX units have six buttons. But I believe that Telex
only used baudot machines (like the M32), not ascii units (like the M33).
More pics here.
|This M33-ASR has a "private-wire" CCU, for 20- or 60-mil current loop use. The CCU panel on the right should be blank, but someone added a light to it. It's getting harder to find the removable copy stand, as well as the plastic (or metal) chad box, which is hanging under the punch on the left.|
|The small box at the top of the stand is the power supply for the tape reader -- in 3300-series machines, this is built into the CCU. In a private-wire unit, like this one, the stand is empty except for the reader supply. In a TWX unit, there is a large dataset (modem) that sits in here.|
|This 33-ASR is pretty clean. Too bad it has chipped plastic at the front.|
|The front unit is the standard tape reader with the three-position START/STOP/FREE lever. The less-common "auto" reader would have a fourth AUTO position -- it could be commanded on and off remotely. The tape punch is the unit directly behind the reader|
|This unit has a Carterfone modem (a third-party modification) added to a standard private-wire CCU.|
|This Carterfone machine belongs to Clarence Turk.|
|The 3300-series machines usually had a one-piece plastic cover, so the tape units did not look like they were bolted-on afterthoughts. I don't know if there was a Model 3300 or not -- the only one I have heard of was labelled Model 3320. The later 33 manuals discuss 3300-series machines, but don't mention specific model numbers.|
|This later 3300-series machine has the auto-reader. The DC1 (XON) and DC3 (XOFF) control characters are used as start/stop commands for the auto tape reader. Since XON/XOFF chars are used today as software-handshaking flow-control characters, you want to disable software handshaking if you are connecting to a 33 with something like a terminal emulation program. Supposedly, DC2/DC4 have been used as auto tape punch on/off commands in the M33asr, but I have not seen any more info on an auto tape punch. Anyone?|
|This 3320 machine has the standard tape reader. Another CCU panel is ruined by hacking lights and switches on it.|
|This 3320 machine has the auto-reader, but not the one-piece case.|
|This is an earlier auto-reader. Too bad the plastic tape cover has broken off.|
|Some TWX machines had an optional auto-dialing card-reader gizmo -- these are blank card that were used with it.|