Title: Hardware Installation Guide.pdf
The RS-232 communications interface is for short distance wiring or point-to-point communications. A number of products provide RS-232 interfaces such as connections to local printer, modem, PC, etc. This interface is intended for a short distance communication because its high impedance is more susceptible to noise. Cable length is generally limited to 50 feet (15.24 m). If required, this distance may be extended to a few hundred feet by using low capacitance shielded cables. The optimal cable is a Belden 9610 or equivalent wire.RS-485 CommunicationsThe (EIA) Electronic Industries Association standard defines RS-485 as an electrical interface for multi-port communications on a bus transmission line. It allows for high-speed data transfer over extended distance (4000 feet/1219 m). The RS-485 interface uses a balance of differential transmitter/receiver to reject common mode noise. For increased reliability over the extended distances end-of-line (EOL) termination is required.RS-485 Line Termination