What is the requirement for fire signal transmissions during fire drills?

NFPA 101-2012 18/19.7.1.4 requires transmission of a fire signal during a fire drill; this requires the fire alarm to be activated. There is an allowance for a coded announcement to replace audible alarms for fire drills conducted between the hours of 9 pm and 6 am in 18/19.7.1.7. This would allow audible annunciators to be silenced prior to the fire drill, but there is no stated relaxation of the requirement to transmit the fire alarm signal. Activation of the fire alarm between 9 pm and 6 am would allow for evaluation (critique) of fire safety equipment other than the audible alarms, visual annunciators, door releases, elevator recall, etc., in addition to signal transmission of the signal to notify occupants and summon staff. The transmission of the signal is not required to go off-site responders during fire drills.