The concept in question is quite simple: a primary LCD would be visible at all times, and when the occasion called for another panel or two, they'd simply slide into view, ready to serve as a number pad, or settings control, predictive text display, or even a full-fledged split keyboard.

ENGADGET

Besides lacking a camera, WiFi, GPS and even music playback (obviously), there's no color display, WAP browser, email client or T9 predictive text (which all came with the T68i), and no GPRS packet data or built-in Bluetooth (which both arrived with the T39).

ENGADGET: Ericsson T28z review Mobile