SWITCH No. 5A-1 and 5A-2

These switches were originally used on the Telephone No. 706, which had provision for one switch only.

It is based on the Switch No. 5A which is just a simple plastic encapsulated, non-locking, change-over switch, which was initially used in the Adaptors, Shared Service No. 3.  This adaptor was effectively a Switch No. 5A-1 with a Thermistor attached.

On the Bakelite models a label was affixed to the case but in the 700 types the button (called a Label No. 358) was embossed or printed upon.

So, for general switching arrangements the Switch No. 5A-1 (non-locking) and 5A-2 (locking) were introduced in 1960.  The difference between the two switches was the plunger, to which the label was affixed.  The locking plunger (Part 2/DPL/372) had a second lug at the button which located on the switch frame, when the button was pressed on the right-hand side.  Pressing on the left-hand side released the button.

The Switch No. 5A is mounted (by two 6BA screws), on a Bracket Mounting, Switch (Part No. 1/DBR/515) and the Plunger, Switch (Part No. DPL/372) is held between the two in a slot, which allows it to slide up and down.  In addition, on the Switch 5A-1, a flat plate called a Plate, Stop (Part 1/DPL/2032) is fitted on the top face of the switch and held in place by one of the switch fixing screws.  This Plate, Stop is probably fitted to ensure that the the button, when pressed, does not tip sideways.

Three wires are connected to the Switch No. 5A and terminated with spade tags.

The button labels would have been ordered separately and are fitted on the top of the Plunger.

The switch is affixed to the telephone by means of the switch frame hook and a screw.

These switches were superseded by the Switch No. 5A-3 in mid 1961.  This switch was supplied with no Plunger or Button Stop and the buttons were the only items required.

Last revised: August 12, 2024