View ltc1690i datasheet:

Final Electrical Specifications LTC1690 Differential Driver and Receiver Pair with Fail-Safe Receiver Output September 1998 FEATURES DESCRIPTION No Damage or Latchup to ±15kV ESD (Human Body The LTC®1690 is a low power receiver/driver pair that is Model), IEC1000-4-2 Level 4 (±8kV) Contact and compatible with the requirements of EIA485 and EIA422. Level 3 (±8kV) Air Discharge The receiver offers a fail-safe feature that guarantees a Guaranteed High Receiver Output State for high receiver output state when the inputs are left open, Floating, Shorted or Terminated Inputs with No shorted together or terminated with no signal present. No Signal Present external components are required to ensure the high Drives Low Cost Residential Telephone Wires receiver output state. ICC = 600µ