Commodore Datasette

[1] Typical compact cassette interfaces of the late 1970s use a small controller in the computer to convert digital data to and from analog audio tones.

After the Datasette's launch, however, special turbo tape software appeared, providing much faster loading and saving.

[1] Such software was integrated into most commercial prerecorded applications (mostly games), as well as being available separately for loading and saving the users' homemade programs and data.

The Datasette has only one connection cable, with a 0.156-inch (4.0 mm)–spacing[6] PCB edge connector at the computer end.

All input/output signals to the Datasette are all digital, and so all digital-to-analog conversion, and vice versa, is handled within the unit.

The motor power is derived from the computer's unregulated 9 V DC supply[8] via a transistor circuit.

[9] To record physical data, the zero-crossing from positive to negative voltage of the analog signal is measured.

The clipped signal therefore fits into the TTL electrical level window of the Schmitt trigger step that in turn feeds the digital cassette port.

In addition to this, some models came with a small hole above the keys, to allow access to the adjustment screw of the tape head azimuth position.

[14] Like Datasette models, the recording format is compatible across computers; the VIC, for example, can read PET cassettes.

[21] In the United States disk drives quickly became standard, despite the 1541 costing roughly five times as much as a Datasette.

In most parts of Europe, the Datasette was the medium of choice for several years after its launch, although floppy disk drives were generally available.

The inexpensive and widely available audio cassettes made the Datasette a good choice for the budget-aware home computer mass market.