The Siemens S40 is a tri-band mobile phone that operates on the GSM-900, GSM-1800, and GSM-1900 networks.
Its more distinctive features include the voice memo recorder, the mute feature for conversations, the ability to record phone conversations, and the ringtone composer (a useful alternative for those unsatisfied with the 47 monophonic ringtones).
[2] The phone also supports WAP 1.1, SMS, HSCSD, and T9 predictive text input.
The S40 includes a 104x64 pixel monochrome liquid-crystal display with a blue backlight, an internal antenna, and rubbery buttons to prevent accidental dialing.
Phone was also branded as the Siemens S42, with the only differences being the keypad cover and a more rounded form factor.