PTC 404

The UK/PTC-404 is a lightweight two wire telephone normally kept and carried in a satchel. Unlike the PTC-414 this does not feature a keypad tone system.

Power Supply

The PTC-404 is powered from 4 x 1.5V batteries ("D" size) which give a total potential difference of 6V. These form the basis for the internal power supply, although the phone can take its power from exchanges or central power banks.

Selection Switches

S1 is a three position rotary switch with the following settings:

• Whisper - Makes use of the whisper speech facility - for more tactical situations
• Normal - The Normal operating position
• Test - This setting checks both audible and visual alarms. With the S2 switch on "RING" then both will operate for 1.5 seconds.

S2 is also a three position rotary switch with the following settings:

• RING - In this position the phone will ring for 1.5 seconds
• MAG (magneto) - This is the normal standby position for working to another phone
• CBX (central battery exchange) - In this position the phone is connected to the Central Battery Exchange

Audible Alarm Volume Switch operates much like any other volume control; it is a rotary mechanism controlling the audio gain ranging from maximum volume to inaudible (off). The use of which will obviously depend on the current tactical situations.

Visual Alarm Control is nothing more than a shutter which can be used to cover the LED to block the visual alarm. This again will be used dependant on the tactical situation.