GSM and PSTN alarm system,gsm pstn system,gsm pstn alarm system,gsm security system GSM and PSTN alarm system,gsm pstn system,gsm pstn alarm system,gsm security systemSystem Features l Large LCD English blue back-light display, voice prompt, ease of use. l Support dual-network of both PSTN landline and GSM mobile network, provide redundancy for extra stability. l Can check status and call records ...