This card has two channels. Each channel is fed by an port RS232 and an RS422/RS485 port; only one of which may be active. The two independent channels may be operated at any data rate from DC to 128 kbps. Data may be RS232/RS422 full duplex, or RS485 half duplex.
They may be used point-to-point, or they may be connected in a series of nodes in an Add/Drop (poll-response) topology.