The RS485 standard addresses the problem of data transmission, where a balanced (differential) transmission line is used in a multi-drop (party line) configuration (or point-to-point if only two devices are on the network). Up to 32-nodes (drivers and receivers) are allowed on one multi-drop, bi-directional network. Data rates of up to 10M bps are supported over short distances (40ft.). At the four-thousand foot distance limit, data rates of up to 100K bps are allowable. RS485 specifies a 2-wire, half-duplex communications bus. Because there are differences between RS485 and RS422 (minor in many instances, except for loading 12K vs. 4K) many people refere to 4-wire RS485. While RS485 is a 2-wire standard, it does offer 32 nodes on a network, on the other hand RS422 (a 4-wire standard) only specifies up to 10 nodes. Therefore, while not technically correct, it does make some sence to refer to a 4-wire RS485 network that would extend the number of nodes on a 4-wire network to 32 standard loads.