SIT491E is a 4. 5V~5. 5V powered, full-duplex, low power dissipation RS-485 transceiver fully meeting the requirements of RS-485 & RS-422 standard. SIT491E contains one driver and one receiver, both can transmit signals independently. The SIT491E has a 1/8-unit-load. It allows up to 256 transceivers on the bus and error-free data transmission up to 12Mbps. SIT491E has a working voltage range of 4. 5V~5. 5V, with the functions of Current-Limiting Protection, Over-voltage Protection, Control Port Hot Plug Input, etc. SIT491E has excellent ESD release capability, and HBM reaches ±15kV.