Installs, tests, troubleshoots, programs, maintains, and repairs digital switching equipment, attendant consoles, power and ringing relay racks, miscellaneous telephone, radio, fire alarms, intrusion alarms, and computer data circuits and related apparatus required in the central switching office. Analyzes system failures and other unusual system occurrences to isolate the source of the problem and determine whether the failure is caused by software, hardware, or other factors. They maintain manual and/or computerized central office records, including detail records, traffic analysis records, cable records, line records, subscriber service records and spare parts inventories.