SINGCALL Wireless Signal Amplifier for The Calling System,To Enlarge Signal Coverage.It Is an Optional Accessory.(APE80) It Can't Be Used Alone!! 01.Can work with all the SINGCALL wireless calling system. 02.The signal amplifier/repeater APE80 can be used directly and the default setting is to transmit the signal of all the pagers used in the place. 03.Need to connect with power adapter. 04.Please draw out the two pieces of antennas and make sure the angle between the antennas and the ground is 45 degree. (Upward at a 45 degree angle) 05.Distance can be 980ft(300m) in doors, 5000ft(1500m) in the open air.