What is "osmocombb"

OsmocomBB (Open Source Mobile Communications – Baseband) is a free firmware for the devices known as " baseband processor" Chipset found in GSM mobile phones.

OsmocomBB implements the GSM protocol stack's three lowest OSI Layers of the client side GSM protocol and device drivers. The protocol layers forming the kernel exists on the baseband processor, typically consisting of an ARM processor and a digital signal processor.