...RS-485
Standard 	EIA RS-485
Physical media 	Twisted pair
Network topology 	Point-to-point, Multi-dropped, Multi-point
Maximum devices 	32 - 256 devices (32 unit loads[1])
Maximum distance 	1200 metres (4000 feet)
Mode of operation 	Differential signaling
Maximum baud rate 	100 kbit/s - 10 Mbit/s
Voltage levels 	        -7 V to +12 V
Mark (1) 	        Positive Voltages (B-A > +200 mV)
Space (0) 	        Negative voltages (B-A < -200 mV)
Available signals 	Tx+/Rx+, Tx-/Rx- (Half Duplex)
                        Tx+, Tx-, Rx+, Rx- (Full Duplex)
Connector types 	Not specified