* Modem 3GP
* GSM Modem
* Modem is an analog modem that converts analog signals into digital signals
* ADSL Modem
o Modem ADSL (Asymetric Digital Subscribe Line) technology that allows Internet surfing and use the analog phone simultaneously. An easy way to ADSL provided a tool called a splitter or divider line. Splitter positions are placed in front when the incoming phone line. This means you can not branch to the ADSL modem line with direct sound. Splitter tool useful for removing noise when you're using ADSL modem. With Splitter both can run simultaneously, so users can answer and call someone with a regular phone. On the other hand, users can still connect to the internet via ADSL modem.
* Cable Modem is a modem that receives data directly from service providers via cable TV
* CDMA Modem
Source : http://id.wikipedia.org/wiki/Modem