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Old 12th Feb 2019, 5:30 pm   #5
russell_w_b
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Join Date: Jul 2007
Location: Penrith, Cumbria, UK.
Posts: 3,684
Default Re: BT Inspiration (+ Versatility etc) PA Connection?

We use a unit made by Baldwin Boxall, which gives an audio output of 0dbm into 600 Ohms (775mV) and has a digital storage device to give a delay. This is necessary to prevent howl-round. Various open collector switches are available too.

It may be possible to make one using bucket-brigade technology but will be disconcerting if the delay isn't long enough, ie a delayed message is broadcast when you are still speaking!

Ours is effectively an analogue telephone extension: dial a 'PA' number, rings three times then speak and hang up. The message is then broadcast.
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Russell W. B.
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