... , enable the system works great in worldwide.◇ 99 zones for security intrusion alarm, elderly care, SOS help, 7*24 hours ... communications, regular phone call as hand set supported.◇ 2 wireless switch channel for remote control & door access (*optional).◇ Just simply ... band 850/900/1800/1900 MHzRadio Frequency: 433.92MHz for sensors, 315MHz for wireless switch (*optional)Digital Output: 1 relay, NC/NO ...