Internal Building Communications

This includes the Doorbell, Intercoms and Panic Alarm. (generaly anything powered by the transformer in the techbox)

Intercoms

Techbox:Show switch, intercom and LED

The handsets themselves are all hardwired together so that when any handsets are picked up at the same time users at each end may communicate. This means that without anyone calling anywhere else, a 4 way conversation is possible. When the phone is called, a loud buzz is produces by the speaker in the headset. If someone has the phone off the hook, you can’t call them (this is a good thing because then you can’t deafen the person holding the handset). Don't try and be funny by phoning yourself, those buttons are disabled so nothing will happen!

The phones are situated in 4 strategic locations around the building:

Number	Location
1	Servery
2	Tech Box
3	Back Stage
4	Box Office
5	Spare/Unused

Back stage the intercom can be silenced by a small switch on the side of the unit. Regardless of whether it has been silenced or not, a small LED on the wall above the table will flash.

In the Techbox, the phones can be silenced using the show switch. When the show switch is activated, the LEDs along the front of the Techbox will flash GREEN instead of hearing a beep.

Panic Alarm

Panic alarm control and reset

There are two panic buttons, one in the box office and one in the café, all members of staff should know how to use them. When they are pressed a blue light flashes in the office, red LEDs flash in the tech box and if box office is pressed, a buzzer sounds in the café. They are reset by pressing the marked button behind the box office. If you press the button you should have several hefty people there in seconds, people are discouraged from playing with it. If you are in another part of the building and the alarm is set of, please send any available personnel the help the panicking FOH staff

TO RESET THE ALARM press the ‘reset’ button on top of the black box in the box office (shown on right)

The alarm is controlled from the black box, the signal and power is transferred through the same wires as the intercoms. The interface of the two systems is in the white box to the left of the black control box

This system has its history in Bedlam folklore but it was modified to include the "silent" running mode with the red and green flashing LEDs around Spring 2000 by the skill and design work of the legendary Steve "Box Office" Fryatt.

In the run up to fringe 2006 the panic alarm was also set up to supply power to the till and replace the tired batteries. However when the panic alarm in the box office has been activated, the system cuts the power and the till will not open

The alarm system is controlled from the black box in the box office. The panic alarm electronics are based around two relay switches this allows the system do be selective. If the box office alarm is triggered, an alarm is sounded in the café whilst cutting power to the box office till. These functions would not be desirable if the café alarm was triggered. The circuit diagram shown above represents one relay.

The pins 1