... rate:250K,receiver sensitivity: less than -100.Product Name: Wireless Voice/Non-visual Doorbell 1,2.4G ISM Public Frequency ... 500 meters for barrier free Details:Wireless intercom doorbell is a set of multi-way intercom system,can be uesd in offices, ... ect.Using the 2.4G Communications Channel, full-duplex interoperability intercom, communication distance up to 500 meters aboveInstructions:1,Boot: ...