Legacy Mutlifunction Ports

Every cable has a connector/plug at the end which plugs into a port

Serial Ports

Serial Ports come with either 9-pins or 25-pins and are male ports. The 9-pin connector is the more common of the two but even these are disappearing from modern PCs.
Serial Ports transfer data one bit at a time. The maximum trasfer speed is 115 Kbps.
Devices that can be connected to Serial Ports are Mice, External Modems, Label Printers, PDAs and digital cameras.
Pins: 9 or 25
Transfer Speed: 115Kbps
Maximum Length: 15.24m

Parallel Ports

Parallel ports are the 25-pin female ports on the back of a PC. They are most commonly used for Printers but have also been used for external CD rom drives, Zip drives and scanners.
Parallel ports transfer one byte (8 bits) at a time.
Pins: 25 or 36
Transfer Speed: 2MBps
Maximum Length: 6m or 10m

IEE 1284B Ports

The IEE 1284B port is used for Printers. It is a parallelhas contacts rather than pins and also a securing mechanism at each end to hold the connector in place.
Pins: 6
Transfer Speed: 115Kbps
Maximum Length: 5m