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300 baud throughput, programs saved twice for internal error checking, check-summing for data files.


Keys for play, record, fast-forward, rewind, and stop. Sensor for software detection of key press. Counter for tape location.


Commodore propriety format using pulse-width modulation and square waves. Allows naming of programs and files, verification of programs, end of tape marker sensing.


Uses standard audio cassette tapes. Digital tapes not required.



The electronics of the datasette contains read/write circuits that replace the audio-type circuits in a standard audio tape recorder.

Status/Motor Control - When the play switch is depressed, a ground potential is applied to the cassette enable line of the microprocessor. It, in turn, signals the cassette drive motor through a transistor switch located on the main computer board. The cassette is then ready for read/write operation.

Write/Record Amplifier - The computer outputs a square wave signal to the datasette. These TTL logic-level shifts are converted by the pre-amplifier and power amplifier to a proportional current output. This current output is then applied to the read/write coil of the head. Through induction, magnetic fields are produced on the tape representing the data.

Read/Playback Amplifier - The read amplifier circuit takes the reproduced transition signals from the tape and converts them back to TTL logic-level shifts. This is accomplished by an amplifier limiter which removes the amplitude variations and a switching circuit that toggles the output data between 0 and 5 volts. The signal is then ready for output to the computer.

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This page has been created by Sami Rautiainen.
Read the small print. Last updated June 08, 1998.