Baseband is commonly known as BB, Baseband can be defined as a communication module. It contains a communication system. It is usually used to control iPhone’s communication procedures, telephone communications, WiFi wireless communications, as well as Bluetooth communications.
The Baseband manages all the functions which require an antenna. The baseband processor has its own RAM and firmware in NOR flash, separate from the ARM core resources. The baseband is a resource to the OS. The Wi-Fi and Bluetooth are managed by the main CPU, although the baseband stores their MAC addresses in its NVRAM.
All iPhones have a baseband, and iPhone baseband is essentially the cellular modem firmware that is on your iPhone. Specifically, baseband includes the low level software that is running on the iPhones cellular modem hardware, the combination of which allows the iPhone to connect to a cellular network to send and receive data, phone calls, and transmissions.
iPhone’s signal is directly related to its baseband IC. Under normal circumstances, if you upgrade the firmware of your iDevice, it’s baseband will follow the upgrade.
Additionally, baseband is also what keeps the device locked to the intended carrier, in the USA, this is commonly AT&T, Verizon, T-Mobile, Sprint, and some smaller other carriers. Buying an unlocked iPhone would not have that baseband lock, for example.
How to check iPhone’s baseband?
A1. Launch Settings app of your iPhone -> click General.
A2. Continue to click About -> Modern Firmware.
The iPhone’s baseband processor is the S-Gold 2.
The iPhone 3G, the iPhone 3GS and the iPad make use of the X-Gold 608 chip for this purpose.
The iPhone 4 (iPhone3,1) and iPad 2 (iPad2,2) use the XMM 6180.
The iPhone 4 (iPhone3,3) uses the MDM6600 and the iPhone 4S uses the MDM6610.
iPad 3 uses MDM9600.
iPad 4, iPad Air , iPad mini, iPad mini 2, iPad mini 3, iPhone 5, iPhone 5c and iPhone 5s use MDM9615.
iPad Air 2, iPad Pro (12.9 inch), iPad mini 4, iPhone 6, iPhone 6 Plus and iPhone SE use MDM9625.
iPhone 6s, iPhone 6s Plus and iPad Pro (9.7 inch) use MDM9635.