Commodore Datassette

The Commodore 1530 (C2N) Datasette, later also Datassette (a portmanteau of data and cassette) is Commodore's dedicated magnetic tape data storage device. Using compact cassettes as the storage medium, it provided inexpensive storage to Commodore's 8-bit home/personal computers, notably the PET, VIC-20, and C64. A physically similar model, Commodore 1531, was made for the Commodore 16 and Plus/4 series computers.

Unlike most microcomputer storage methods using compact cassettes, the Datasette uses a digital format. Instead of writing two tones to tape to indicate bits, patterns of square waves are used including a parity bit. Programs are written twice to tape for error correction; if an error is detected when reading the first recording, the computer corrects it with data from the second. The Datasette has built-in analog to digital converters and audio filters to convert the computer's digital data into analog sound and vice versa. Connection to the computer is done via a proprietary edge connector (Commodore 1530) or mini-DIN connector (Commodore 1531). The absence of recordable audio signals on this interface made the Datasette and clones the only cassette recorders usable with Commodore computers, until aftermarket converters made the use of ordinary recorders possible.

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