... homes, clubs, etc. Wireless Calling Service System / Table Calling System / Hotel Service System:Main function:(1) The system is made up of one receiver ... 1 pc 12V 23A battery), HE Calling transmitter (optional), HJ Multi-function calling transmitter (optional), HB Infrared inductive alarm transmitter (optional ... , worker, sickbed, or other places you can use this calling system.