(a) Provisions shall be made so that a small current flow to constantly supervise each circuit shall be maintained on every closed circuit electrically operated interior fire alarm system. A milliammeter or other approved current indicator shall be provided and so connected as to indicate the supervising current.
(b) The supervising circuit shall be provided with a trouble bell operating on open circuit arranged to ring continuously in case of failure of the system. The trouble bell shall be so located that will be within audible range of some responsible person in the building and shall be connected to the electric light or power service in the building.
(c) Trouble bells shall not be fitted with silencing switches except in such a manner that the act of silencing the bell by the operation of a switch automatically and positively transfers the trouble signal to a red lamp, fed by some auxiliary source of current supply, on the control board. This auxiliary source of current supply may be a house lighting circuit or any other approved source.
(d) Trouble bells shall be an approved vibrating type and shall give a distinctive signal.
(Ord. No. 991-49. Passed 6-27-49, eff. 6-27-49)