The M301 provides two asynchronous serial interfaces based upon the MC68681 DUART. The line interface of a channel can be configured as RS232, RS422, RS485 or current-loop (active or passive). The RS232 and RS485 transceiver devices are commonly available and are mounted in sockets for easy maintenance.

Features
> 1 Mbits/sec maximum data rate
> RS232 / RS422 / RS485 and 20mA current-loop (TTY) modes independently selectable per channel
> Hardware handshake (RTS/CTS) for point-to-point transmission modes (RS232 / RS422)
> Line-break detection and generation
> Baudrates independently programmable per channel