Port powered RS-232 to RS422 / 485 converter - dip switch selectable between RS-422 or RS-485
Provides RS-232 to RS-422 / RS-485 conversion using either port-power or an external power supply
Db9 female to terminal block
Brand name (s) : B&B Electronics

Data is converted in both directions, RS-232 Transmit Data is converted to balanced RS-422 or RS-485 Transmit Data. Received RS-422/485 signals are converted to RS-232. Unlike converters which require programming hardware handshaking signals to control RS-422 or RS-485 operation - "Automatic Send Data" Control is a feature of this product.

Features:
In RS-485 mode, the RS-485 driver is enabled by circuitry which senses the RS-232 TD input.
In half-duplex RS-485 mode, the receiver is enabled when not transmitting.
For full-duplex operation, the receiver is set always enabled.

Manufacturer datasheet - 4WSD9TB (Adobe Reader required to read datasheet)