|P.O. ENGINEERING DEPT.
Issue 2, 1937
POLICE TELEPHONE AND SIGNAL SYSTEM, USING
SWITCHBOARDS, PA 101
1. Post, PA No. 1
specially-constructed street pillar, known as Post, PA No. 1 is provided to
accommodate all necessary equipment for a street call-point.
2. Public door
The head of the pillar is of triangular shape. One side carries the protecting grille, the
public call door with its buffer-closing device, and the pin for operating the impulse
3. Maintenance door
On another side is the maintenance door, which is hinged along the bottom and fixed on top
with two captive screws of triangular shape, for which a special tool known as Key,
Pillar is required.
4. A flat-headed adjustable screw is provided in this door to press the plunger of the
power switch, which completes the local power circuit for the signal light when the door
is closed and cuts off the power circuit when the door is open.
5. Police door
T he third side contains a door which is kept locked and through which access is obtained
by means of Key, Lock, N, to the police side of the apparatus.
6. First-aid compartment
The body of the pillar contains a compartment for the accommodation of a First-Aid Outfit.
The door of this compartment is not locked, and has only to. be pulled open in order to
gain access to the First-Aid Outfit; the Outfit, if required, will be supplied and
maintained by the Police Authorities.
7. Base of pillar
The power supply, and telephone lines, are led-in underground to the base of the pillar.
The power fuses are fitted on a board fixed across the base, and the telephone protector
is fitted on a board fixed vertically inside the pillar from base to top. This board
accommodates the power and telephone leads on opposite sides with ample clearance. The
boards are supplied as part of the pillar.
8. A maintenance door is provided in the base, and is fixed with four of the special
triangular-headed screws, requiring the use of Key, Pillar.