Audio broadcast via a physical wire

[kadiot]

Is there a way to broadcast emergency messages via cable radio? Its not really radio but audio going out from copper or fiber using existing landlines or CATV cables. No tuner needed, could just be a speaker. The system I am looking for does not need internet or mobile connections. I imagine it is an analog connection via a physical wire. But instead of listening to an audio recording via a handset, we can listen through a speaker.

Thank you.

 

[anorlunda]

Yes. It was invented by Alexander Graham Bell.

 

[kadiot]

Yes. It was invented by Alexander Graham Bell.

Yes, but how? Do you have the technology? Care to share? Thanks.

 

[anorlunda]

Yes, but how? Do you have the technology? Care to share? Thanks.

https://patents.google.com/patent/US244426?oq=ininventor:alexander+ininventor:bell+telephone

 

[kadiot]

https://patents.google.com/patent/US244426?oq=ininventor:alexander+ininventor:bell+telephone

Thank you for the link. it seems that Bell's patent is for 2 way communication. What I am looking for is a one way transmission of audio but going out into a receiver not a handset.

 

[Rive]

What is the expected range?

 

[kadiot]

Here is the rationale:
1. Use of landlines is declining
2. In a disaster or emergency, cell sites may not work
3. Not everyone has UHF or VHF radio
4. In many places, landlines are still available or operational
5. AM and FM radio could still work, but additional means would still be welcome 6. cable radio going through landlines is one possible additional means

 

[anorlunda]

It sounds like you're talking about a remote address public address system. The man in the weather center shouts TORNADO into the microphone, and every house has a speaker to repeat that. Is that it?

Radio is better suited for that. The maintenance cost of landlines is extremely high. Think of all those crews you see parking their work truck near the road with a whole crew of men standing by.

Edit: A siren is also better for that purpose.

 

[chemisttree]

Edit: A siren is also better for that purpose.

But how will we tell the difference between an Amber Alert and a tornado warning and 12:00 noon and...

 

[anorlunda]

But how will we tell the difference between an Amber Alert and a tornado warning and 12:00 noon and...

They already do that. They have coded pulses (blasts) for different events. There is not necessarily a code for all possible alerts, but enough.

I once lived in a village which had fire alarm boxes mounted on the telephone poles. Each one had a code identifying the location. (The alarm box was an automated telegraph, yet another Thomas Edison invention.) At the fire station, they repeated that code on the siren so that firefighters could respond directly to the scene rather than going to the firehouse first. If I remember right, it was a two digit nonary system, which allows for 81 locations.

 

[russ_watters]

Radio broadcast:
https://en.m.wikipedia.org/wiki/Emergency_Alert_System

Landline alert:
https://en.m.wikipedia.org/wiki/Reverse_9-1-1

I suspect this audible alarm is wired, but don't know for sure:
https://www.pge.com/en_US/safety/em...clear-power-plant-emergency-notification.page

But its purpose is just to tell you to turn on a tv or radio. Radio use may be declining somewhat, but it is still pretty ubiquitous.