I just finished scanning, optimizing, cropping, combining, and OCRing the 1920 edition of NFPA 72. In 1920 document numbers weren't used but rather its title:

Regulations

of the

National Board of Fire Underwriters

for the installation and use of

Signaling Systems

Used for the Transmission of Signals Affecting the Fire Hazard

as recommended by the

National Fire Protection Association

Edition of 1920

Code weenies may find this interesting. Charlie Trout answers a question regarding the voltage-drop requirements of NFPA 70 on the NECA-NEIS Code Question of the Day web site.

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