|P.O. ENGINEERING DEPT.
Issue 2, 1938
POLICE TELEPHONE AND SIGNAL SYSTEM
(USING “SWITCHBOARDS, PA 150 AND 150 TD“)
This Instruction describes the specially-constructed street pillar, known as “Post, PA, No. 1“, which is used to accommodate all the 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 door-closing spring and the pin for operating the impulse mechanism.
3. Maintenance door
On another side is the maintenance door, which is hinged along the bottom. The door is secured with a captive screw with a triangular-shaped head on the outside, and with a captive thumb-screw on the inside, access to the screw being gained from the police compartment. A “Key, Pillar” is required for use with the external screw.
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
The third side of the pillar contains a door which is kept locked and through which access is obtained, by means of a “Key, Lock, N” to the police microtelephone. This side is also provided with a “Desk No. 18” to facilitate the writing of notes by police officers.
6. First-aid compartment
The body of the pillar contains a compartment for the accommodation of a first-aid outfit which, if required, is supplied and maintained by the police authorities. 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.
Base of Pillar
7. Base of pillar
The power supply, and telephone line wires, 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 and a “ Block, Terminal, No. 20/4” are fitted on a board fixed inside the pillar (see
picture). This board accommodates the power and telephone leads on opposite sides with ample
clearance. The boards are supplied as part of the pillar.
A panel giving access to the telephone. line terminating equipment and power fuses (see
picture) is provided in time base and fixed with four special triangular-headed screws, requiring the use of “Key, Pillar”