Disaster Message Dial is NTT's voice message service activated during major disasters. Dialing "171" and entering a home phone number as the key allows recording and playing back 30-second voice messages. Even when call lines are congested, message recording and playback remain relatively smooth.
Usage is simple: dial 171, press "1" to record or "2" to play, then enter the disaster area phone number (with area code). Up to 20 messages per number are stored for 48 hours. Available from landlines, mobile phones, and public phones, free for both recording and playback.
The service activates for earthquakes of seismic intensity 6-lower or above and major storm/flood disasters. NTT offers practice sessions on the 1st and 15th of each month, during Disaster Prevention Week (8/30-9/5), and Disaster Prevention and Volunteer Week (1/15-1/21).
A web version "Disaster Message Board (web171)" enables text-based safety registration. Mobile carriers offer their own disaster message boards. Families should agree to "check disaster message dial using our home number as the key." See disaster phone guide for detailed instructions.