For Immediate Release
March 6, 1997

NTT Develops PHS/GSM Dual-Mode Handset
- Promoting PHS in countries utilizing GSM -

Nippon Telegraph and Telephone Corporation (NTT) announced today the development of a prototype handset for the transmission of signals for the Personal Handy-phone System (PHS)*1 and the Global System for Mobile Communications (GSM) *2. The new dual-mode handset combines the superior aspects of PHS and GSM functions to achieve high-quality performance.**

NTT is striving to develop PHS business in various mobile communications environments overseas. The company will utilize this handset in its efforts to provide PHS services outside of Japan, thus helping promote the introduction of the PHS into countries using the GSM.

** As telecommunications carriers are not permitted to transmit GSM radiowaves in Japan under current regulations, NTT has developed a system simulator to accurately reproduce the GSM network environment. In addition, NTT has conducted appropriate quality evaluations of the connection and voice transmission of the new handset. Results indicate the handset's high-quality performance.

Attachment

1. Development Background

As NTT works to promote its PHS business overseas, it is vital that the company take appropriate steps to introduce PHS services that conform with each market's communications environment. For example, some countries or regions may seek PHS services to supplement current GSM services in order to overcome frequency shortage in urban areas, set up call areas in underground malls, and realize lower call charges. In such countries and regions, the need for services that employ a single handset with both PHS and GSM functions is expected to emerge.

2. Technological Points

1) Automatic connection to the most appropriate system through agent function
In striving to develop handsets for use in both PHS and GSM environments, NTT applied an agent function to radio communications. "Agent" refers to a concept in which communications devices and networks can realize the specific communications needs of users. The newly developed handset allows the user to utilize control-software to switch between the private PHS mode (home cordless telephone and wireless PBX), the public PHS mode, and the GSM mode. The user can also automatically connect to the lowest-cost system that offers maximum quality in accordance with surrounding radiowaves. Such features contribute to the considerable advantages offered by the PHS over conventional services, while ensuring the lowest call charges.
2) Realization of similar capacity and weight as the GSM handset
The new dual-mode handset weighs 280 grams with a capacity of 290 cc, similar to the widely used GSM handset.

3. Future Plans

As part of efforts to develop its PHS business overseas, NTT will introduce the new handset at various seminars and exhibitions overseas, conducting demonstrations using the simulator to promote the scope of application and compatibility of the PHS in various communications environments.

4. Terms

*1) PHS

The system has more than five million subscribers in Japan. Compared with conventional cellular telephone services, PHS services offer larger transmission capacity, superior voice and data transmission, longer talking time and stand-by time, and lower call charges. The PHS can be used not only outdoors as public mode but also in homes and buildings as private mode.

*2) GSM

GSM was developed in Europe to enable the use of cellular car telephones across national borders. GSM services cover a wide call area from a single base station, and GSM handsets can be used in fast-moving automobiles. The GSM is currently used in more than 100 countries, mainly in Europe and Asia. It is becoming the world's de facto standard.


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