Tired of pushing tiny buttons to key in text messages on your mobile phone? Siemens AG has developed a prototype phone in the shape of a pen that allows you to write letters and numbers on any surface and enter the data directly.

The prototype PenPhone features integrated handwriting recognition technology, in addition to standard features of a mobile phone based on the GSM (Global System for Mobile Communications) technology. Siemens Mobile, the wireless division of the German manufacturer, will demonstrate it at the Cebit trade show in Hanover, Germany, next month, a company spokeswoman said Monday. The pen is aimed largely at heavy SMS (Short Message Service) users, who today face the tedious task of keying in messages manually by pressing buttons for each character.

"The PenPhone is able to recognize whatever letters or numbers you write on any surface," the spokeswoman said. "It translates the handwritten words or numbers directly into an SMS, which appears on the display."

The device is 140 millimeters long with a diameter of 19 millimeters.

The Siemens spokeswoman declined to provide further details about the PenPhone ahead of the Cebit show, saying only that interested users will be able to test the device for themselves at the annual computer exhibition.

Munich-based Siemens said it has not yet decided whether the pen will go into production.