Notice

NTT Communications Corporation

UPDATE: Service Disruption (May 31, 2004)

To Our Valued Customers:

We would like to inform you that the recent service problem was caused by a magnetic contactor (MC) error within the power distribution frame located in the Otemachi building. The MC inappropriately disconnected the circuit for a reason that has yet to be determined.

Commercial power to the Otemachi power facility is provided from a dual supply route, as we also have our own generator and battery backup system. Using this backup power supplying system and the UPS which has a bypass function installed, we have been able to provide our data services without prior incident, even during periods of blackout.

We will continue to investigate the full reason for the occurrence of this problem. In addition, we will take the following steps in order to prevent the problem from occurring again:

• Check all of the other 70 nationwide power facilities within this month
  
• Enhance system reliability, such as by diversifying power distribution frame and UPS
  
• Review the HVAC system in power source facilities
  
• Relocate service equipment separately in order to minimize area affected by potential future disorders (in the unlikely event that any should occur)

We sincerely apologize for any problems to our service that resulted from this incident.

Sincerely,

NTT Communications Corporation