Actually Sprint, Vorizen, altel , and cricket are CDMA and TDMA carriers. the big GSM carriers ar T-mobile and cingular. CDMA carriers hav 2-3 frquencies max GSM carriers have 4 frquencies somtimes 5 Japan uses UMTSSprint and Verison are both GSM type carriers. Cingular and t-mobile are some other type of network that I should remember but dont.
question; i thought cell phones operated on different frequencies or networks or whatever... ex. i believe sprint uses a different type than verizon. is this not true?? and if it is, doesn't that mean a jammer would have to be tuned to work against a certain carrier?
Verizon and Sprint = CDMA
Cingular and T-Mobile = GSM
Alltel can go ether way but they are mostly CDMA (they have alot of gsm coverage in the north and south Dakota areas). They do operate on different frequency's. The frequencies are purchased from the FCC and they vary in different areas. Also each BTS uses a different frequency from its adjacent cells. This way the signal from one tower doesn't interfere with the other. Mobile Stations are told what channel or frequency to move too between hand offs.
The firmware idea is interesting but could require getting really down in it. I was working on a firmware issue on a GSM PC Card and at a certain point in we needed an adapter between the PC and the Card. Needless to say reverse engineering the things would be no small undertaking. Easier to customize your own jammer/transmitter.
spint is curently equiping their CDMA network with WIMAX wich is a 4G format.
GSM carriers are using HSDPA rogers wirless (incanada) is beta testing hardware for HSDPA.