Model 422PP9R is a port-powered, two-channel converter that changes TD and RD RS-232 lines to balanced RS-422 signals extending communication distances up to 1.2 km (4,000 ft.). Automatic Send Data Control feature enables the RS-422 driver when data is present on the RS-232 side. Control of the driver is automatic at rates up to 115.2 kbps. The RS-422 driver and receiver are always enabled. With port-powering, a power supply is not required. Power comes from the DTR and RTS RS-232 handshake control lines. At least one handshake line must be present, in either the Positive or Negative voltage state. This permits use in applications without worrying about software control of the handshake lines. The converter is configured to transmit data in both directions in an RS-232 and RS-422 system. The RS-232 pin-out connects directly to a computer’s COM port or any other DTE device. Model 422PP9R connections to the RS-422 side are made via a DB9 connector. This converter is ideal for field service or "in-line" cable applications.