Telecommunications facilities are governed by NFPA 76, a separate standard from the NFPA 75 requirements that apply to information technology equipment, and the distinction is substantive rather than administrative. NFPA 76 is written around the specific characteristics of carrier infrastructure: enormous concentrations of cable, DC power plants with large battery strings, signal continuity obligations, and facilities that are frequently unstaffed for extended periods.
Cable is the dominant fuel load. A central office or major carrier room contains cable mass in quantities that exceed almost any other occupancy, routed through risers, trays, and raceways that provide continuous vertical and horizontal propagation paths through the building. NFPA 76 and NFPA 70 address this primarily through cable listing and flame spread requirements, because controlling how the fuel burns is more tractable than suppressing a fire distributed along hundreds of feet of tray.
The operational constraint is continuity. A telecommunications facility carries traffic that includes emergency services, and the DC power plant is designed to keep it carrying that traffic through utility outages. That creates the same tension generator rooms face: a protection scheme that de-energizes equipment to make the room safe also drops the service the facility exists to provide. Combined with unstaffed operation at remote sites, where nobody is present to respond to an alarm, this makes very early detection and remote notification more valuable than fast suppression.