RS232 TO RS422/RS485

Description

Our RS232 to RS485 / RS422 adapters are ideal for connecting devices which use RS485 or RS422 to an RS232 port.

They are available in non-isolated and isolated models. On the isolated model, the isolation circuit provides an optical barrier between the RS232 and RS422/485 bus connected to the unit, helping to isolate harmful spikes and surges which may occur on the bus. The isolated models also features built-in surge protectors to further protect against spikes, surges and electrostatic discharge.

A set of DIP switches allows selection of RS422, RS485 full-duplex or RS485 half-duplex on the RS422/485 side. Internal termination and bias resistors can be enabled via internal jumpers.

The unit features automatic transmit-enable for RS485 which avoids the need to do this via manual control of RTS. In RS422 mode the transmitter is always on.

This unit uses a universal switch mode PSU (supplied) and unlike many inferior products does not rely on borrowing power from signal lines on the host RS232 port which can cause operational issues and unreliable operation.

It has both screw terminal and DB9 connector options for connectivity on the RS422/485 side.

• Convert an RS232 port to an RS422 or RS485 port
• Available in Optically Isolated version
  • 2000 Volt DC optical isolation
  • RS422/RS485 port with surge protection on signal lines to protect against ESD and surges
• RS232 via DB-9 female connector
• RS232 port can be selected to a DCE or DTE pin assignment
• RS422/RS485 via DB-9 male connector and 5-pin terminal block (subset of signals)
• Data rate: 300 bps to 1M bps
• Auto transmit/receive control for 2-wire RS485 half-duplex operation
• Auto RTS/CTS handshaking in RS422 mode (DB-9 connector)
• Termination and bias resistors on-board and selectable by jumpers
• Signals
  • RS422: Tx-, Tx+, Rx+, Rx-, GND, RTS-, RTS+, CTS+, CTS-
  • RS485 (full-duplex): Tx-, Tx+, Rx+, Rx-, GND
  • RS485 (half-duplex): Data-, Data+, GND
• Power, TxD and RxD indicator LEDs
• Requires external PSU (supplied)
• Wide input power range: 9V DC to 48V DC (ES-R-2x01B-M)
• Wide input power range: 9V DC to 36V DC (ES-R-2101C-M)
• Operating temperature of -20°C to +60°C
• Robust metal enclosure with mounting ears

 
NOTE : This product comes supplied with a universal switch mode PSU and unlike many inferior products does not rely on borrowing power by stealth from the host RS232 port with unpredictable results.  Nor does it rely on using the RTS signal to switch the data direction in RS485 mode - this is done automatically by the hardware. It has both screw terminal and DB9 connector options for connectivity.

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