ERICSSON
SWITCHBOARD No's N500, 509, 510 & 515

N510

These switchboards, while giving the same facilities as N515 type, have been specially designed to meet the demand for a cheaper article for mines where cast-iron explosion-proof cases are not essential.

The casework is constructed of hardwood of robust proportions and the sloping top is reinforced by a heavy-gauge steel plate which provides ample protection against falling roof material and water. A special triangle-headed screw lock is fitted and a suitable key for same is provided.
The indicators, mounted on the steel front plate, are protected by a watertight cover and are reset by turning the knob at the right-hand side.

The connecting keys, comprised of stout metal plungers fitted with metal tops, will withstand a considerable amount of rough usage. The tops are engraved to indicate the connections made when the keys are depressed.

The terminals are mounted on ebonite strips screwed to the backboard and are very accessible.

A blind back is fitted to protect the interior from dust, moisture and unauthorised interference.

This form of cordless switchboard is widely known as the "Pyramid" on account of the design formed by the keys. The simplicity of operating and obvious low maintenance costs have made them the general favourites for small magneto systems.

N509 introduced in the Ericsson Telephone Catalogue, edition No. 26, Supplement 1935

Taken from the Ericsson catalogue, edition 26

Last revised: November 24, 2025