27 Communications
27.01.00 Operation and Maintenance of Communications Systems
27.01.10 Operation and Maintenance of Structured Cabling and Enclosures 27.01.20 Operation and Maintenance of Data Communications 27.01.30 Operation and Maintenance of Voice Communications 27.01.40 Operation and Maintenance of Audio-Video Communications 27.01.50 Operation and Maintenance of Distributed Communications and Monitoring