Tarbell Cassette Interface

[2] At the time, it was considered to be fast, reliable, and popular, and became a de facto standard for compact cassette data storage.

This is accomplished by reading a byte into a shift register which is periodically triggered by a 555 timer.

On reading, the system uses clock recovery to calculate the original data rate to account for tape stretch and other effects.

This means the data can be recorded at any hardware-supported rate, and the manual suggests up to 560 bytes per second.

The latter includes a Tarbell floppy disk interface, said to plug into any S-100 bus computer, introduced in 1979.