Magneto, Mining, Wall Switchboard
This switchboard complies with the requirements of the Coal Mines Act and is recommended for use underground, or in exposed positions on the surface, when it is desired to branch several telephone lines to a central point.
Communication can be established separately with any section.
Each section can communicate with any other section.
Several sections can be connected together.
All sections can be connected in bridge with the controlling telephone, and yet, should a fault occur on any section it can be rapidly isolated and so maintain the rest of the system in working order.
These and many other features are invaluable, especially in an emergency.
The cast-iron case is explosion-proof and watertight: the inner compartment being sealed by an inner door fastened with heavy machine screws arranged for attaching a seal, if desired the outer door when closed giving thorough protection.
The push and pull type connecting keys, the mechanically-restored indicators protected by a glass fronted cover, and all working parts are of a specially robust pattern, suitable for the conditions met with in mines. Provision is also made for connection of an external alarm bell.
Telephone instrument N2980 or N2981, is required to operate the switchboard and should be fitted at the right-hand side near the switchboard, as the front doors will then open away from each other and thereby give better facilities for operating.
This switchboard is made in one size only, namely, for a maximum of six lines, but partially equipped boards can be supplied.
|N515||14 x 13.5 x 10||55|
Taken from the Ericsson catalogue, edition 26
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