So many unanswered questions

[323]

I have so many questions that, even after hours of scouring the internet, I've found no answers to.

1.) How do cellphones work? Specifically, I mean. Not looking for an answer like "They send the signal to the cell tower, which sends it to a satellite." I mean things like what the signal contains data-wise, what the signal is transmitted in (Is it like TCP/IP or something?) How do the phones know you have a voicemail, like how do they contact your voicemail to check if one is there? How can calling internal numbers (Internal AT&T numbers like "*639#", "611", and "*2" (Those are all that I know)) check to see if your phone has the latest firmware or see how long you have left on your contract, etc? Is there a list of #'s that do things like that somewhere?

Those are pretty much questions that only people at cell phone companies would know. One person probably wouldn't even know all of that, just part of it. Then I would have to ask another person for another part, etc. Problem is, I don't know anyone at AT&T or Sprint or Version or anything.


Well, after trying to remember so much about that question I forgot the others ;_; I'll edit this post when I remember them.

[Kain]

I have so many questions that, even after hours of scouring the internet, I've found no answers to.

1.) How do cellphones work? Specifically, I mean. Not looking for an answer like "They send the signal to the cell tower, which sends it to a satellite." I mean things like what the signal contains data-wise, what the signal is transmitted in (Is it like TCP/IP or something?) How do the phones know you have a voicemail, like how do they contact your voicemail to check if one is there? How can calling internal numbers (Internal AT&T numbers like "*639#", "611", and "*2" (Those are all that I know)) check to see if your phone has the latest firmware or see how long you have left on your contract, etc? Is there a list of #'s that do things like that somewhere?

Those are pretty much questions that only people at cell phone companies would know. One person probably wouldn't even know all of that, just part of it. Then I would have to ask another person for another part, etc. Problem is, I don't know anyone at AT&T or Sprint or Version or anything.


Well, after trying to remember so much about that question I forgot the others ;_; I'll edit this post when I remember them.

There's no real transmission protocol, it's just waves sent over the air, like radio.

Phones know you have voicemail because the server that receives it sends a signal to your phone to tell it it does, and continues to send it until your phone 'acknowledges' it.

The internal numbers send a rapid request to your phone (outside the range your speakers can play), to which your phone replies, giving it the information it needs to inform you of updates, etc. (for more info on how stuff like that works, google 'phone phreaking captain crunch')