NTT's Disaster Emergency Message Dial
171 - NTT's Disaster Emergency Message Dial
Because landline and mobile phone service can be patchy during a disaster, NTT provides a phone message board during times of disaster by dailing 171. You can leave and listen to messages, and it is a good way to find out the status of someone you are searching for during an emergency. Calls can be made from public payphones as well.
For more information on how to use the service, please see the description on NTT's website:
Other cell phone providers may also provide similar services, so please check with your cell phone company for details.