Rockmount Electronics Wireless Home Business Security Burglar Alarm and 4-Band GSM 850/900/1800/1900 Cellular All-In-One System ES10GSM-10w3m For details of this system, please google ROCKMOUNT ELECTRONICS 4-Band GSM Frequency: GSM850 / 900 / 1800 / 1900. Worldwide compatible. No landline needed. Type: Wireless Digital. No interference. Accept 99 sensors (32 wireless /7 wired zones) Control: panel, keyfobs, remote access via phone, Text message control Warranty: Free one year warranty and unlimited technical support