RS-232 to 4x RS-485 /2x RS-422 Converter
ADA-1044H

RS-232 to 4x RS-485 /2x RS-422 Converter* The prices are given in the response to the offer.
The ADA-1044H changes RS232 standard to RS485/RS422 and can be use for creation star-topology on RS485 Bus. To one converter it is possible to connect two or four segments (1200m) of RS485 Bus without interfering with the format of transmitted data. This converter has one RS232 port for connection Master device (PC, PLC-MASTER) and four separate RS485-ports for 2-wire bus or two RS485/422 for 4-wire bus. The setting of port type is by "RS-485 PORTS" switch on the front panel. ADA-1044H can be used also for communication with devices in star topology located in different places where RS485 chain topology is impassible.
To the RS485-ports can be connected 64 devices for 4-wire RS485 bus, 128 devices for 2-wire RS485 bus or 2 addressable devices with RS422 interface. The converter does not required powering form RS232 port, supports asynchronous baud rate up to 230.4 kbps by one or two pairs of twisted-pair RS485/422 interface.
ADA-1044H has female DB-9 socket for connection of RS232 interface and screw terminal block for power supply and twisted-pair connections of RS485/422 network. Connector DB-9F is made like DCE, it let connect converter to other device using the extension cable RS232 (typical cable for modem connection) without crossing TX with RX, RTS with CTS, DTR with DSR. The converter uses signals Rx, Tx and GND of RS232 interface (looped signals in the connector RS232 DB-9F: DTR-DSR-DCD, RTS-CTS), entered by DB-9F socket.
Overvoltage protection on each line of RS485 / RS422 is made on the basis surge suppressors diodes and fuses.
Example of connection ADA-1044H converter