KDDI Corp. unveiled Japan's first smart phone compatible with the WiMAX high-speed network Monday, aiming to differentiate its lineup from other carriers' and keep pace with the smart phone trend.

Running Google's Android operating system, the HTC EVO WiMAX ISW11HT has a 4.3-inch multitouch screen and will debut under the au brand sometime after early April.

"In the era of smart phones, you can't really experience the merits of smart phones without a fast network," said KDDI President Takashi Tanaka during a preview event in Tokyo, referring to the frequent interruption of video clips caused by slow Internet connections.

With a maximum download speed of 40 Mbps and upload speed of 10 Mbps, the WiMAX network is several times faster than the mainstream 3G network. Currently, au's 3G network speed is 9.2 Mbps for downloading and 5.5 Mbps for uploading.

"It's a superfast smart phone. Once you use it, you won't be able to go back to (slower networks)," said Tanaka, who used to head UQ Communications Inc., which operates the WiMAX and is a KDDI affiliate.

The EVO, which can work on the 3G network and has been popular in the U.S., works as a wireless router as well and can connect up to eight devices through either 3G or WiMAX. Users pay ¥525 a month to get unlimited WiMAX service in addition to the regular monthly fee for the 3G Internet connection.

While the Japanese cell phone market has been rapidly shifting to smart phones, carriers have found it difficult to get their products to stand out from the crowd. Under the circumstances, Tanaka said, a network can be one means of attracting notice.

While admitting that WiMAX will eat into revenue from the 3G network, Tanaka said, "I'd like to prioritize giving a sense of excitement."