I've been looking for various GSM and cellular modules to use in a mobile phone. There are plenty of big gsm modules and gsm modems out there, but they're big and expensive. Most of them are designed for remote data collection and the like. I'm trying to build a cellphone.
From where can I find the simplest 2G or 2.5G GSM(or equiv) module or
modules that takes voice and dialpad data and uses an antenna? Cost size and power are all issues.