Model 485CARLP9A is an RS-232 to RS-485 converter that allows you to connect your laptop PC to Carrier branded HVAC equipment.

Model 485CARLP9A is a port-powered, half-duplex RS-232 to RS-485 converter with send data control. The unit converts TD and RD RS-232 lines to balanced RS-485 signals and supports three-wire (Data A, B, and Signal Ground reference) RS-485 communications only.

The converter is powered from the RS-232 handshake lines, RTS, CTS and DTR, DSR, CD. The handshake lines are looped back on each other and can be in either state. No handshake change is necessary – no software is required to control the lines.

The RS-485 driver is enabled with each bit of data. The RS-485 receiver is disabled when the driver is enabled and enabled when the driver is disabled. This prevents data from being echoed back into the RS-232 device. The RS-232 side has a DB-9 female connector. The RS-485 side has a six-position RJ11 connector.

Note:  Some names and words are trademarks of their respective owners. Carrier is a part of UTC Climate, Controls & Security, a unit of United Technologies Corporation ("UTC").