not seeing it in 72???
with modern technology if you use a radio not needed, unless local thing
internet monitoring, not needed, unless local thing
this might be it::
nfpa 72 2010
26.6.2.6 Dual Control.
26.6.2.6.1 Dual control, if required, shall provide for redundancy in the form of a standby circuit or other alternate means of transmitting signals over the primary trunk portion of a transmission channel.
26.6.2.6.1.1 The same method of signal transmission shall be permitted to be used over separate routes, or alternate methods of signal transmission shall be permitted to be used.
26.6.2.6.1.2 Public switched telephone network facilities shall be used only as an alternate method of transmitting signals.
26.6.2.6.2 If using facilities leased from a telephone company, that portion of the primary trunk facility between the supervising station and its serving wire center shall not be required to comply with the separate routing requirement of the primary trunk facility. Dual control, if used, shall require supervision as follows:
(1)
Dedicated facilities that are able to be used on a full-time basis, and whose use is limited to signaling purposes as defined in this Code, shall be exercised at least once every hour.
(2)
Public switched telephone network facilities shall be exercised at least once every 24 hours.
