NATIONAL TELEPHONE COMPANY
B20

Magneto Wall Sets

Pattern No. B20

Comprises - Hand combination Transmitter and Receiver, Cord, Automatic Cradle-switch, Induction Coil, Lightning Arrester, 4 Magnet Generator, Bell, Battery Box and Writing Desk with Paper lip.

This is a large size instrument and the generator will ring satisfactorily through the 300 ohm bell of the instrument, and a line resistance or 25,000 ohms.

Taken from the 1903 Catalogue.