TheoryPhone was released on 1996 only in blue and was released in the variety of colors (red, lime green, purple, black, silver, teal and gold, etc.) on April 29, 1997.
- GSM 900/1800 MHz
- Call and text messaging, voice dial, etc.
- 2-inch monochrome display
- Mobile chat mode for SMS
- StarWeb WAP browsing
- Pre-loaded games: Snake, Space Strike, Cards, Pac-Line
- "The new silent mode can now let you enjoy peace, while you are busy dodging bullets and grazing them."
- - Announcer on commercial
An early commercial in 1998 features a man at an arcade playing Touhou 10: Mountain of Faith. While he is fighting the stage 5 boss Sanae Kochiya, his phone rings and since he can't let go of the joystick, he bites down on it while using his hand to get out his TheoryPhone device. After calling, an animated Reimu Hakurei (voiced by Wendee Lee) shows up and teaches the man on how to use Silent Mode on his phone. After Reimu realizes the joystick is filled with saliva, she performs a purification ritual to remove the slime. A male announcer then gets on and explains silent mode.