CONV232/485 and CONV232/422 convert between RS-232 communications (as used by the COM1 and COM2 ports standard on most motherboards) and balanced-mode, long distance RS-485 and RS-422 communications. CONV232/485 was designed for use with our REMOTE ACCES line when there is no RS-485 port on your PC, but may also be used in other, similar applications.
CONV232/485 supports two-wire RS-485 communications, which is half-duplex (only one may transmit at a time) but allows up to 32 participants on a "party line" network. CONV232/422 supports four-wire RS-485 and RS-422 communications, which only allows two peer participants (or one master and multiple slaves) but is full-duplex (both peers, or the master and one slave, may talk at the same time.) CONV232/422 can also support two-wire RS-485 if the transmit and receive pins are tied together, but in this configuration it echoes on the RS-232 side.
Internally, TD and RD are converted to balanced lines and the RD line is automatically disabled when data is being transmitted to the RS-485 network. The converters can transmit and receive transparently at whatever speed the data is flowing, up to 460K baud for the CONV232/485 and 230K baud for the CONV232/422. CONV232/485 (and CONV232/422 in a two-wire RS-485 configuration) can support up to 31 other RS-485 devices (with the optional external power). CONV232/422 in a master-slave configuration can support up to 31 slave devices.
The converters plug into your RS-232 port, and all you need to do is hook up the RS-485 wires via a DB9 Male connector. Optional external power is required when communicating with more than two REMOTE ACCES Pods, or over long transmission lines; if external power is not provided, power drawn from the DTR and RTS lines on the RS-232 port is sufficient where the communication cable is short and there are few nodes.
