The BL1585B is an integrated circuit (IC) from Belling that transmits and receives RS-485/RS-422 serial data signals up to 500 kbps in half-duplex operation. Size-wise, the BL1585B is an 8-pin plastic small-outline package (SOP) measuring roughly 150 mils. It operates on a voltage range of 4.5 to 5.5 volts, and is in accordance with RoHS standards, meaning it does not contain any hazardous substances. The BL1585B is a single port chip, capable of transmitting and receiving on one port only.