NATIONAL TELEPHONE COMPANY
B21

Magneto Wall Sets

Pattern No. B21

Comprises - Hand Combination Transmitter and Receiver, Cord, Automatic Switch-hook, Induction Coil, Lightning Arrester, 3-Magnet Generator, Bell, Battery Box and Writing Desk (with Paper clip or Writing Tablet).

This instrument is of ordinary size and the generator will ring satisfactorily through the 300 ohm bell of the instrument and a line resistance of 20,000ohms.

Taken from the 1903 Catalogue.