• The bi-directional connectors of this converter are mainly used between the main controllers.
• The RS232 to RS485 converter can transfer TXD and RXD signals from the RS-232 interface and at the same time after transmitting RTS 7-pin data terminal DTR to support the delivery of this converter.
• RS232 to RS485 Transmitter Converter Communication Data Adapter
• The RS232 converter ensures that you need to reset it and make easy application of hardware and software installation.
• 

Bi Directional Communication RS232

Serial port function: simultaneously compatible with RS-232, RS-485 standard of EIA/TIA.
Electrical interface: DB9 hole interface of RS-232 end, DB9 pin plug of RS-485 end, compatible with post (5 ports)
Working methods: asynchronous half duplex.
Tran..media: common wire, double wire or UTP or shielding line.
Transmission speed: 300-115-21BDS
Transmission distance: 5 meters (RS-232 end) 1200 meters (RS-485 end)
Telecommunications agreement: transparent.
RS232 adapter working environment: -10 degrees Celsius to 85 degrees Celsius, relative humidity: 5% to 95%
RS485 Converter Signals:RS-232:TXD, RXD, RTS, CTS, DTR, DSR, DCD, CND; RS-485; Data+, Date GND
Item:RS232 to RS485 Converter
Dimensions: 9.8 x 3.2 x 1.7 cm
Weight:74g    en.wikipedia.org

RS232-485 converter can transfer the TXD and RDX signals of RS-232 serial port to parallel half-duplex RS-485 signals without external power source because it can collect electricity supply Pin 3 RS-232 port and also