Isolated In-line Serial Converters Models 4WSD9OTB and 4WSD25OTB convert RS-232 to RS-422 or RS-485 (2 or 4-wire). 2,000V two-way optical isolation protects devices from power surges, spikes and ground loops in harsh electrical environments. These in-line converters support distances up to 1,200 m (4000 ft.) and data rates up to 115.2 kbps. Switchable modes support 2-wire RS-485, 4-wire RS-485, and full duplex RS-422. Available with female DB9 or DB25 RS-232 inputs. Removable terminal blocks for RS-422/485 and external power make wiring easy. Accepts external power from 10-48 VDC from an industrial power source or plug in power supply. The power supply is sold separately