The Commodore C16, C116, and Plus/4 share a 7-pin mini-DIN cassette port, used exclusively with the Commodore 1531 Datasette unit. This port superseded the 6-pin PCB edge connector found on the earlier VIC-20 and C64, adding a second ground pin (pin 7) while retaining the same functional signals: power, motor control, read, write, and sense. Data is stored using audio-frequency FSK encoding, with the cassette motor switched under software control to keep tape movement synchronised with data transfer.
7 PIN MINI-DIN FEMALE at the computer
| Pin | Name | Dir | Description |
|---|---|---|---|
| 1 | GND | - | Ground |
| 2 | +5V | OUT | +5 Volts DC |
| 3 | MOTOR | OUT | Cassette Motor |
| 4 | READ | IN | Cassette Read |
| 5 | WRITE | OUT | Cassette Write |
| 6 | SENSE | OUT | Cassette Sense |
| 7 | GND | - | Ground |
Signals
- GND — Signal and chassis ground; provided on both pin 1 and pin 7.
- +5V — Regulated +5 V DC supply to the Datasette electronics.
- MOTOR — Motor remote control output; the computer switches this line to start and stop the cassette transport under software control.
- READ — Audio data input from the cassette playback (EAR) output; carries the FSK-encoded bitstream read from tape.
- WRITE — Audio data output to the cassette record (MIC) input; carries the FSK-encoded bitstream written to tape.
- SENSE — Detects when the play button on the Datasette is pressed, allowing the computer to respond to user-initiated tape operations.
Notes
- Direction is Computer relative to Datasette.
- The 7-pin mini-DIN connector is mechanically and electrically incompatible with the 6-pin PCB edge connector used on the VIC-20 and C64 (Datasette models C2N/1530). Do not attempt to cross-connect them.
- Pin 7 (GND) is an additional ground not present on the 6-pin edge connector; signal functions of the remaining pins are otherwise identical between the two connector families.
- The Commodore 1531 is the only official Datasette for this port; the earlier 1530 and C2N models use the 6-pin edge connector and are not compatible.