Aaeon MB-562 Manual page 40

The MB-562 offers four serial ports: three RS-232 (COM1/CN15,
COM2/CN17, COM3/CN14) and one RS-232/422/485 (COM4/CN20).
These ports let you connect to serial devices (a mouse, printers, etc.)
or a communication network.
Normally, the parallel port is used to connect the card to a printer. The
MB-562 includes two on-board parallel ports, accessed through CN19
(a DB-25 connector) and CN16 (a 26-pin flat-cable connector). You will
need an adapter cable if you do not use a traditional DB-25 connector.
The cable has a 26-pin female connector on one end and a DB-25
female connector on the other.
32 MB-562 User's Manual