The term i-mode refers to an Internet connectivity service for mobile phones that was introduced by the Japanese company NTT DoCoMo™ in 1999. It is somewhat unique in the field of mobile device technology in that it does not use the Wireless Application Protocol (WAP) like most other mobile devices, but instead uses a packet-switched protocol, similar to what hard-line connections use. The main protocol it uses is an adapted form of Hyper Text Markup Language (HTML) called Compact Wireless Markup Language (CWML). It also uses two of its own protocols known as ALP and TLP, which act in a similar way to HTTP and Transmission Control Protocol (TCP), respectively.
The i-mode service, despite its use of a different protocol to connect, operates in similar ways to WAP-enabled services. It has access to many services such as e-mail, stock market services, sports results, telephone banking, and overall Internet connectivity. One disadvantage of both WAP and i-mode is that the services it offers have to go through a conversion process, and either they are converted beforehand for specific use with a compatible device, or the services are passed through larger gateways that convert them before they reach the user. Mobile phones, and other portable devices, that operate more like a personal computer (PC) don’t have that problem, and instead they connect directly to the source.
Another possible disadvantage is the pricing structure. The i-mode service charges for the use of the service as well as a fee for both data sent and received. Other services that use the PC model of communication usually charge a flat fee. While the fee structure allows NTT DoCoMo™ to have more control over its charging, the consumer typically pays less in a flat-fee structure.
Despite the possible disadvantages, the use of i-mode is still prevalent in Japan. As of 2008, NTT DoCoMo™ reported that it had 48 million subscribers, compared to its approximately 5.6 million in 2000. There was a concern that originally there would be a conflict between the WAP services and i-mode, but that did not pan out.
Even though the use of i-mode is primarily in Japan, it also has users in other countries. Over time, the service has been gradually phased out of many of the European markets. Several Asian markets still retain use of the service, however. Despite this continued use many experts, including the inventor of i-mode, have stated that they believe devices that use TCP/IP connectivity, the same protocol PCs use, will eventually take over the market because they require less adaptability.