A mobile device that could be described as the first VoIP-only mobile phone has been launched in Japan by JAJAH and EMOBILE.

The EM-ONE device uses the JAJAH mobile software client to make and receive calls using mobile broadband, so it does not require a traditional mobile connection.

VoIP products by the companies have already proven popular in Japan, with an outbound-only service gaining thousands of users.

EMOBILE customers pay a monthly fee of around £2.50 and receive a Direct Inward Dialling number which turns the EM-ONE device into a phone with no cellular connection.

EMOBILE chief executive Kengo Masuda said: "To build a revolutionary device in the most advanced mobile market is a real achievement, and we are very proud of what EMOBILE and JAJAH have been able to accomplish together."

The service should be available to the entire Japanese population by August 1st.

Asia has a huge telephony market and the analyst group Ovum recently predicted that it will grow by 1.6 billion connections to 3.8 billion by 2017.