OEM, Telebyte Interface Converter RS-232 to RS-422 Model 253
.DB9 Data Port
Compatible with PC/386/486
Full Duplex
Surge Protection
The Model 253 Interface Converter does this for full duplex signals at data rates up to 19.2 KBPS, without requiring any AC or DC power. With only TD, RD and ground, the Model 253 provides operation over 8,000 feet of twisted pair into a load of 120 Ohms. The Model 253 features a female DB9 connector, thus allowing it to be plugged directly into any one of the PC's Com ports. When using the Model 253 in this mode the DTE/DCE switch is positioned to the DCE position. . Model 253 Specifications
Interface: COM PORT Complies with RS-232 for signal levels and PC Com Port for connector type and pin assignment. RS-422 Port complies with RS-422 for signal levels and phasing.

Data Rate: 0-19.2KBPS

Operating Distance: 8,000 feet

COM PORT Transmission Controls: CTS (Pin 8 turns on immediately after the PC raises RTS (Pin 7); DSR (Pin 6) and DCD (Pin 1) turn on immediately after PC raises DTR (Pin 4).

Connectors: PC side-DB9 Female 422 side - Screw terminals, RJ-11 or RJ-45, ordering option

Power: None required, uses TD as power source.

Size: .85" H (21.6 mm) x 1.3" W (33mm) x 3" L (76.2mm)

Weight: 0.8502 (29 gm)

Environment: 0° to 50° C, 0% to 95% RH

MTBF: 693,000 Hours (79 Years)
USED,clean, Excellent Condition. Compared new @ $79.00 $$$SAVE$$$ Used our price $39.00 as pictured Sorry, no returns on electrical parts. stk#(2544)A4 ,B1