One after another, PHS operators have launched services that display messages on PHS terminals. Known as the “Short Message Service,” the service is used primarily by young customers.

There are two types of service: Realtime Transmission Service and Storage Service.

Realtime Short Message Service enables direct communications between PHS terminals. Users can exchange messages in realtime and check for incoming messages. However, messages will not be received by PHS terminals that are turned off, or out of service areas.
Storage service, however, assures message delivery. Messages are stored at the message center even when receiving terminals are off or out of service areas. Users are notified about their mail, and can then download the messages onto their PHS terminals.
Both services are very popular as they enable easy communications with PHS terminals. The percentage of Short Message calls in all PHS calls has been increasing rapidly. For instance, one PHS operator handles more than 1 million Short Message calls a day, accounting for 15% of all its PHS calls.
The success of the Short Message Service may be attributed to a trend among some of the eight million pager subscribers, who seem to be switching over to PHS. The Short Message Service, which enables realtime communications, will expand the current message communications market.
To encourage this trend, PHS operators have been upgrading the service. A variety of functions have been added to the Short Message Service since the autumn of 1997, including one for sending messages directly from the Internet to PHS terminals, one for sending a single message to multiple receivers, and one for notifying the arrival of e-mail messages. Not only characters but also symbols and signals can be sent with the service. A news service is also under consideration.
PHS operators and manufacturers all consider the Short Message Service one of the most important value added services for promoting further penetration of PHS. And they have built Short Message Service functions into almost all PHS terminals to further encourage use of the service.
However, the service cannot be used between PHS terminals provided by different PHS operators, because the Short Message Service technologies have been independently developed by operators and manufacturers. To ensure compatibility between PHS terminals in the near future, PHS MoU Group is considering formulation of technical standards for the Short Message Service.