Features include ...

RS422 (4-wire) and RS485 (2/4-wire) models available
Isolation 100% tested at >1000V AC
Plugs directly into IBM PC serial port
Very low cost
No separate power supply required in most applications
Baud rate independent 0-38 kbaud
Latest surface-mount technology
Controlled slew rate driver for low emissions
MIL-STD conformally coated circuitry
Surge-protected RS422/RS485 inputs

Do not confuse these isolated models with imitations which claim to be self-powered but which in fact require power to be supplied to both sides of the converter, or which require about 40mA - far too much for any PC interface to supply.

The following PDF data sheet covers all product versions in the DB25-DB25 package:

RS232 to RS422
RS232 to 4-wire RS485 (Master)

K422-ISOL

The K422-ISOL is an isolated RS232-RS422 converter for up to 38400 baud. It is intended for full-duplex point to point communication. It can also be used as a Master on a 4-wire RS485 bus.

RS232 to 2-wire RS485

K485-ISOL	The K485-ISOL is an isolated RS232-RS485 converter for up to 38400 baud. It is intended for 2-wire RS485 applications. RTS Control is required from the RS232 device.