UT-2201 interface supports 2 communication modes as below: 1. Point-to-point 2 wires half-duplex 2. Point-to-multipoint 2 wires half-duplex When converter works under half-duplex connection, it needs to install a matching resistance (data 120 ohm1/4W) for signal reflection and interference. UT-2201 half-duplex communication connect between interface converter 1. Interface feature: -232C, -485 standard interface compatible with EIA 2. Electric interface: -232 end DB9 hole connector -485 end DB9 needle connector with connection pole. 3. Working mode: asynchronism half-duplex (-485) 4. Transmission media: twisted -pair or STP 5. Transmission rate: 300-115.2KBPS 6. External discharge dimension: 63mm x 33mm x 17mm 7. Working circumstance: - 25 to 70 degree C, relative humidity 5%to95% 8. Transmission distance: 1,200m(-485 end) 5m(-232 end) 9. : DOS/WIN95/WIN98/WIN2000/NI/XP/Linux and so on 10. Applies to all communication software, plug and pay 11. Max 32 pieces face devices can connect 12. Power: serial port charge pump driving technology, no need external power, real 3 wire communication (TXD, RXD, GND), no need initialize serial port 13. Auto send/receive data, without external flow control signal () 14. serial port rs232 material: plastic Color as shown Package Contents: 8 x RS232 TO RS485 Converter Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.