2-95. A TTSB provides functional signal support for corps and division operations. TTSBs provision communications and information systems support to a theater army headquarters, their subordinate units, and as required, to joint, inter-organizational, and multinational partners throughout the area of responsibility. The TTSB and its subordinate units install, operate, maintain, and defend the Department of Defense information network-Army (DODIN-A). Each TTSB leverages the extension and reachback capabilities to provide joint communications and information systems services to the GCC and subordinate commanders to conduct mission command. (See FM 6-02 for more information on the TTSB.)