Dual Band 900 - 1800 MHz, 1 or 2-line connection to the GSM AMR Audio Coding telephone switch (PBX) to notify the caller (optional) telephone switch (PBX) 12kHz charging station use as security and safety alarm message transmission on GSM signal status indicators on the level and easy to use opportunity to change the SIM card eject button for easy SIM card slots External Antenna Kit (Optional) EMI & RFI screen protected aesthetic and compact design Low power consumption (5W) All telephone exchanges (PBX) is compatible with all GSM networks with the opportunity to use secure conversation Radiation ineffective