B&B Electronics 422PP9TB

Port Powered Converter RS-232 to RS-422, 2 Channels, DB9, Terminal Block, 115.2Kbps The 422PP9TB is a port-powered two-channel RS-232 to RS-422 converter. It converts TD and RD RS-232 lines to balanced RS-422 signals. The unit can be powered from the RS-232 handshake lines, DTR and RTS. If port-powering the unit, at least one of these handshake lines must be present, but can be in any state. The 422PP9TB can also be powered externally on the terminal blocks. The RS-422 driver and receiver are always enabled.

To satisfy the requirements of some software packages, the RS-232 handshake lines are looped back (tied together). RTS is connected to CTS, and DTR is connected to DSR and DCD.