gol706
Member
There's something "weird" about text messages. I don't get all the technical wiz but from my understanding it's not really data OR voice.
Somebody wanna step up and explain in simple English?
My understanding, at least as to how it works on GSM networks, is that there is a separate control channel that is used for things like your cellphone broadcasting it's presence to the nearest tower and negotiating switching from one tower to another while you are driving. This channel is much smaller than the channels that carry data and voice, but it is sufficient for these sorts of "I am here" messages. For SMS they decided that there was a small amount of extra space in the existing control messages that could be used to for sending text messages. That is also why SMS is limited to 140 characters, and also why some say it costs carriers nothing to send SMS messages that they charge 20 cents for.
MMS messages on the other hand are a different beast entirely, and usually go over data channels since there is no way a picture or video could be fit into 140 bytes.