Wireless Alarm Systems Support GSM and PTSN Dual serial ports Wireless Alarm SystemsFeatures:*Dual serial ports, access to wired and wireless ... address recording, arm/disarm timely and freely*Wireless equipment status checking, wireless alarm linkage*Telephone line cut alarm*Indication ... be closed*Build-in 10XAA rechargeable batterySpecifications: Wireless Alarm Systems JD-ST-IV GSM Optional