NATIONAL TELEPHONE COMPANY
B61

MINING TELEPHONE SETS

Pattern No. B61

Comprises - Granular Carbon Transmitter in specially constructed Iron Box, Double Pole Receiver (fitted with strong Gun-metal Case. and metal Cap to protect the Terminals from Damp, etc.), Cord (encased in flexible tubing), Automatic Switch-hook, Induction Coil and Push Button.  There is also a 4.5 inch Bell, provided with Packing to protect fittings from moisture, etc.

This Set has been specially designed for use in mines, and clamp situations where telephones are subject to hard wear, and its adaptability to such purposes will readily recommend it. The outer case consists of a cast iron box, the front fastened with screws, packing being first placed between the two surfaces.  The Transmitter, Automatic witch, Ringing Key, and connecting Terminals, are fitted inside on a slab, and the wires connected to them arc formed into a cable which is drawn through a short length of India-rubber tubing.  These, and other means are adopted to prevent as far as possible the access of moisture.

Taken from the 1903 Catalogue.

Last revised: November 17, 2025