Data communications is generally classified into two systems, circuit switching and packet switching. In case of the circuit switching data communications system, one user occupies one channel with high data transmission capability each; thus, this would be rather suitable for continuous and large capacity data communications such as file transfer.
On the other hand, in case of the packet switching data communications system, channels are used only when packet data are sent; thus, this would be suitable for intermittent data communications such as e-mail, web browsing, etc. for multiple users to share the channels instead.

As for the PHS, circuit switching wireless data communications system called PIAFS (PHS Internet Access Forum Standard) has already become available. However, taking an increasing data communications traffic for web access, etc. into consideration, still there are strong demands for packet switching system as well.
In response to these demands, on June 1, 2001, DDI POCKET, Inc. launched new packet data communications service called "Air H"."

1. Outline of " Air H" "

" Air H" " enables data communications at more inexpensive rates through packet communications in addition to the existing 64kbit/s circuit switching communications. Upon introduction of the packet communications, DDI POCKET has also realized further large-capacity and lower costs for H" service, which is efficient for wireline usage, through the use of IP-based networks (exclusive use for data communications) in wireline sections.