Tue Feb 19, 2019 11:28 pm
I know that sirens now mainly use DTMF tones for activation. But from what I heard, sirens back in the 70s and 80s used phone line control. Now, I have really no knowledge when it comes to any form of Dial-Up or any line control in general. Could someone explain to me phone line control was operated? I’m really curious.
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