Dreamcast Technical Pages
SonicTeam's Games for DoCoMo's i-mode Mobile Phones

Overview of DoCoMo and i-mode

DoCoMo is Japan's leading mobile phone provider and the company with the most mobile phone subscribers in the world. DoCoMo is a crude abbreviation for "Do Communication Over the Mobile Network" and was formed by Japan's giant communications company NTT (Nippon Telephone and Telegraph) in 1992.

DoCoMo's i-mode ('i' for information) mobile phones allows the access of cHTML webpages (compact HTML, which is a subset of HTML), and email with a connection that it is always constant. No need to dial into a network, as you are always on the network. i-mode runs on a packet-switched network, that allows NTT to deliver a high volume of access at low cost. Transfer speed is limited to 9.6K/sec, but that is plenty since the average homepage size is 1.2 kilobytes and emails are limited to 500 bytes (each phone can store up to 100 emails). DoCoMo has plans on upgrading their network to 300K/sec in the near future.

Internet access through i-mode phones is growing by leaps and bounds and the number of i-mode customers in Japan now exceeds 18,432,000 as of January 28, 2001. The latest statistics can be found here.

On January 26th, 2001, DoCoMo released new set of i-mode phones that have a new capability called "i-appli" (information application), which means mobile phones that have the ability to execute Java programs or specifically Java 2 Platform Micro Edition (J2ME), which is a version of Java that was designed to fit into small devices like mobile phones, PDA's, etc. These Java programs can be downloaded off of the network and stored on a mobile device, so that the program can be executed each time with having to downloading it first. Some of the very first programs to be made available is games by SEGA's SonicTeam!

i-mode phone example
Display Resolution: 96 x 108 pixels to 120 x 130 pixels (depends on phone model)
Color Range: monochrome, greyscale, and 256 color models
Transfer Speed: 9.6KB/sec (300 KB/sec expected spring 2001 with the introduction of world's first W-CDMA network)

SonicTeam's i-mode Games


Samba de Amigo

Chu Chu Puzzle

Chu Chu Edit

Now that DoCoMo has conquered Japan, they have their sights set on the world. They have made alliances with KPN Mobile of the Netherlands and Italy's Telecom Italia Mobile, to introduce i-mode phones into Europe, and it looks like they will be partnering with AT&T Wireless in the United States, as they bought 16 percent of that company on November 30th, 2000 for US9.8 billion. It's quite possible that over the next few years, i-mode may very well catch on in North America and Europe, and will eventually be offered on third generation (3G) mobile phones. i-mode will have plenty of competition though, as the other major mobile phone providers have competing systems in the market place already, or are about to introduce such systems, and those mobile phones will also have the ability to allow constant access to the internet and be able to download, execute and store Java (J2ME) programs.


i-mode links i-mode FAQ
SonicTeam's i-mode website page (Japanese)
Sega Corporation news release on SonicTeam's i-mode games (Japanese)
NTT's Docomo website
Mobile Media Japan news site
Time article on DoCoMo
Sun Java article describing SEGA games using Java