1) Is this true
From my understanding there are really 2 types of cell networks in uses GSM and CDMA based ones. GSM is mostly used everywhere and CDMA mostly just US , Canada and a few others.
Or am I wrong and there are many others

2) Most GSM phones have a GSM sim card that if the phone is unlocked can beable
to use the phone on any GSM based providers network.
Does CDMA based phones work the same way i.e CDMA sim card that if the phone is unlocked can provide the phone with the options of being able to be used on any CDMA based providers network. Or does CDMA not uses sim cards and uses another mechanism to store phone data and authentication stuff ?
(note I am only talking about smart phones obviously there is trac phones , pay as you go phones , and other non-based smart phones that are fixed when bought i,e there is no sim and they are usually throw away cheap phones that are specially made for one network are very restrictive and really cann't be changed without recreating the phone from scratch almost)

3)
Is gsm sim cards physically different then cdma sim cards (if these exist) or can one uses gsm in a cdma phone and visa versa provided the phone is unlocked?
Obviously if the phone doesn't support the frequency band , authentication protocal or the modulation/demodulation scheme then NO. But do mostly all smartphones have the capabilities to modulate/demodulate gsm or cdma based signs. (i.e all possible cell signals and it is just in the sim card or authentication protocal that must be tweaked )

 

Hello,

Perhaps this page will give you an idea:
http://www.privateline.com/mt_cellbasics/index.html

This link comes from the EDUCYPEDIA page on GSM:
http://educypedia.karadimov.info/electronics/rfgsm.htm

Bertus

 

Thank you those links help better understand the terms and structure

The confusion comes from not realizing that a cell is a geographic area, not a point

and cell sites is the location point of antenna and equipment to except the signal from the phone/devices.

What I am confused about a little bit is at the cell site once the call is excepted by the site how does it get transmitted to the PSTN or other places along the way do all the cell sites have a dedicated line or phone line or is there some wireless relay based machine to send the signal wirelessly. It seems that it would be defeating the purpose of wireless networks if they need a cable on the back end to each cell site. Or is this required like a home wireless access point to a modem / router

I understand that it is convenient still for the cell phone customers but for the setup team of each cell site they would still have to run a line from a cell to another place / phone station ,...etc is that not true do they do the back end to get it to the PSTN wirelessly as well?
If not what cableing topology do they uses mesh (god help us that would be alot of work running all those wires)

I know in theory one would not need to uses much cabling just have the cell phone tower connect to the next local cell site to relay.
I would assume all it does is act as it being its own cell phone and queries the local cell sites around it for info on which one it should send it to probably based on BGP protocal and some wireless relay hardware ...

 

never ,mind

BSC station can act like an adoc relay to the THE MSC OR MTSO.

So most of it can be done with no wires physically connecting the 2 places.

Though I am wondering onces it gets to the THE MSC OR MTSO site where that places is where landlines , and other technologies are glued together so there it must have a few physical lines connecting to the PTSN or if not then the PTSN end most at least have a wirelss pickup that can pick up there stuff.

But my thought is THE MSC OR MTSO has at least a directly to the PSTN (well at some point wires start to come in the problem is where MSC/MTSO out to PSTN I believe

I also answered my question above so all set for now

Though spoofing/fooling THE HLR. VLR, AC, EIR databases would be somewhat tricky at times
Well at least you could if you wanted to be bad DOS the mobile networks by spoofing the code number the mobile gsm networks look up

I call it code # hjacking

 

whats the difference between this two. Aside from what you just wrote from your post?