... GSM networks High sensitivity quad band industrial module for clear voice quality Provide up to 30mA output current for payphone ... connection 2 SIM cards (SIM 1 + SIM 2), 3 standby channels (GSM A + GSM B + PSTN) 5 ... to 106 KPa GSM parameters Frequency bands: GSM 850MHz, GSM 900MHz, GSM 1800MHz (7 kinds) GSM 1900MHz, GSM 850/1900MHz, GSM 900/1800MHz, GSM 900/1900MHz ...