This unit was mounted on the Ferranti Argus 700 Desk Unit. It is basically a Teletype model 33 chassis in a larger enclosure with built-in power supplies, paper tape punch and a paper tape reader.

The Teletype Model ASR-33 was a very popular model of teleprinter. Introduced about 1963 by Teletype Corporation and designed for light-duty office use, it was less rugged and less expensive than earlier Teletype machines or its heavy-duty cousin, the Model 35-ASR.

The Model 33's printing mechanism was an array of levers, cranks, and a type cylinder on a movable carriage. The Model 33 printed up to 10 characters per second. Printing was limited to the upper case ASCII character set.

"ASR" stood for "automatic send and receive." The ASR-33 had a built in paper tape reader and tape punch and used eight-bit ASCII code including one parity bit. It could print and read or punch tape at the speed of ten characters per second. The ASR-33 tape reader was purely mechanical; eight spring-loaded probes would be thrust into the tape, one character at a time, and an assortment of rods and levers would sense how high the probe rose, which told it whether there was a hole in the tape at that position

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