All three machines are based on Intel's XScale processor running at 400MHz, have a four-inch Polysilicon TFT LCD screen capable of 240 by 320 pixel resolution and 65,536 colours, running on Microsoft Pocket PC 2002 software.
The main hardware difference comes in the amount of user memory with the Genio-e 550GS offering 64Mbytes and the 550GX and 550GX/MD models, both featuring 128Mbytes.
Toshiba says the latter two models are designed for business users and the company has also preinstalled ClearVue Office software in the PDA, which allow users to view PowerPoint or Excel data files. The latter version, the 550GX/MD, comes with a 1Gbyte IBM Microdrive hard disk drive which is plugged into the PDA's Compact Flash card slot. The PDAs also have a Secure Digital memory card slot.
The third model, the 550GS, is entertainment orientated and has a companion earphone with inline remote control. All three models have support for MP3 and AAC audio files and also the SD-Audio format, which is used to store music purchased and downloaded from kiosks in some convenience stores in Japan.
All three PDAs measure 125mm by 76.5mm by 15.9mm and weigh 170 grams. The 550GS will go on sale in Japan next week for around ¥60,000 (£315), the 550GX will debut a week later for around ¥70,000 (£365) and the 550GX/MD will be available from late November for around ¥100,000 (£522).
Toshiba said it has no immediate plans to put the PDAs on sale overseas.