... batteries, it can at least work for 8 hours after power cut12) With LCD display13) Remote display box for option14) ... strong vibration situation or strong electromagneticwave.2) Please unplug the power source and telephone lines to avoid lightning strike 3) The meter ... ) Keyboard: six function keys8) Dialing method: DTMF9) Access: PSTN10) Power: AC 220V, 50/60Hz, DC 9V, 800mAh11) Battery: fully charged ...