Latest Case on Mobile Centrex/PHS’ Power As One Choice

By Mr. Tetsuya Hayashi Editor-in-Chief Nikkei Communications NIkkei Business Publications, Inc.


It is a pride of PHS that it‘s now taking overwhelming share on the market of mobile Centrex. PHS has both private and public standard. It is considered easier to construct a mobile Centrex system based on private standard. The following contents, including the market trend and services of mobile Centrex were introduced in the presentation by Mr. Hayashi.

Mobile Centrex is a service based on a company network, which allows the utilization of cellular phone or PHS as a part of the company‘s extension. The background that brought the mobile Centrex concept into prevalence is that mobile enterprises start to turn their focus on company users as the personal mobile market becomes mature in Japan.


From the standing point of a company, mobile Centrex are adopted for the following two purposes.

1.    To realize a higher productivity

  • There‘s only one mobile that a staff needs to take. By replacing the conventional type of inconvenient handset with a mobile fitted in PDA and other necessary functions, business efficiency improves.
  • In addition, although a mobile backs up message-recording from an incoming call when it is necessary, the work to take a message doesn‘t usually happen because the staff can carry the handset around and receive calls addressed to him directly.

    • 2.    To realize the reduce of communication cost

  • Entrusting a third party for PBX maintenance business is no longer necessary.
  • Certain company reported that 70% of the total telephone cost happened with mobile service. Staffs favor mobile even when therefre fixed-line. For that reason, the phone bill shrank.

    • 29.5% of the companies in Japan adopted mobile Centrex system by 2005. Among them, 97.2% are internal PHS system. But these PHS terminals are used only for extension, and there are a lot of forms to use cellular phone outdoor.

    Users need one single terminal that can be connected as extension as well as for outside communication.

    In addition, we have expanded the data communication utilization scene above the voice communication. While the service to access internal mails and groupware are being developed, the security measures are not neglected. If terminals corresponding to this kind of service can be developed, mobile Centrex is likely to spread more. Presently we have already had PDA terminals and security terminals like W-ZERO3. A security terminal must hold the remote control function so that data can be locked up remotely once the handset is lost.

    Centrex is operated not only in a form that makes use of PBX, but also in FMC/FMS form, whose network provides PBX function. For example, when service is offered with only a mobile network, it works in a form that the network traces the location of a call so that charge can be discounted for those calls within the home zone. Besides, a new service form like cordless handset for family use, called Femto-cell has appeared. Femto-cell is, as a matter of fact, a concept of PHS. The concept of PHS is to apply a cordless phone at home for outdoor use. Mobile operators have eventually come back to the point where PHS has reached.

    As was described above, one more function of PHS, which suits not public but private network, that is Centrex service, was developed. It is believed that PHS will keep developing and expanding with the communication speed being accelerated day by day.

    (compiled by Mr. Sato at Hitachi, Ltd.)