28 30 00 Electronic Detection and Alarm 28 20 00 Electronic Surveillance 28 13 00 Access Control 28 10 00 Electronic Access Control and Intrusion Detection / Surveillance 27 41 00 Audio-Video Systems 27 21 00 Data Communications Network Equipment 27 20 00 Data Communications 27 13 00 Communications Backbone Cabling 27 10 00 Structured Cabling 27 04 00 Audio-Video Systems

28 40 00 Electronic Monitoring and Control 28 30 00 Electronic Detection and Alarm 27 53 00 Distributed Systems 27 51 00 Distributed Audio-Video Communications Systems 27 41 16 Integrated Audio-Video Systems and Equipment 27 41 00 Audio-Video Systems 27 04 00 Audio-Video Systems 27 00 00 Communications 21 00 00 Fire Suppression 10 44 00 Fire Protection Specialties