Description

The RS-232C port is the standard port for the RS-232 interface.

Only a few machines have this port as the RS-232C interface is optional in the MSX standard.

For the machines without this port:

• this port will be present on an external interface inserted in a cartridge slot
• this cartridge slot can also be a modem with built-in RS-232C interface
• some Toshiba and Mitsubishi machines are conceived to integrate an internal RS-232C interface, sold as a kit to be build in the computer

For more details, check this page: RS-232C Interfaces

Two different connectors can be found on the MSX hardware for the RS-232C port: DB-25 and DE-9.

Pinouts

DB-25 port

Note: the table below lists the full pin mapping, however most (all?) implementations only implement the minimum to support a Modem or Terminal, as that is all that is required according to the MSX RS-232C specification. As such you may find that only Pins 1-8, 20 and 22 are actually connected.

DB-25 Female diagram

DB-25 Male diagram

DE-9 port

This port is often, incorrectly, called DB-9. The correct name of the port is DE-9, and it is the same connector as used for the MSX Joystick port, although electrically incompatible!

DE-9 Female diagram