Hezbollah fighters mostly communicated using codewords on low-tech walkie-talkies, while command posts and bunkers were linked by the group's fiber optic network. Hezbollah relies heavily on cell phones to conduct its operations, both using existing Lebanese carriers and operating its own cellular networks. Limited numbers of high-ranking and critical personnel have satellite phones as a redundant measure. Hezbollah's communications network has greatly increased since 2006, and fiber optic cables links the homes of top commanders to bunkers and headquarters. Normal personnel have access only to the insecure copper wire network, which is supposed to be used only for casual conversations. Hezbollah did not have direct communications with the IDF in 1999, but apparently did in 2009.