... order, in North America, Central America,Caribbean and South America,GSM Network frequency is: 850/1900Mhz or Quadband 850/900/1800 ... ) ) 14)Locking PIN/ Network (optional) Specifications:1.Air Interface Standard: GSM 900/1800 MHz Phase 2+2.Frequency Ranges:Transmission ReceptionGSM ... ring -when alarm panel answer call, fwt detect "DI-DI" sound from panel, then send DTMF '*' to panel, then detect "DI ...