RE: Re: How do I tell whether the phone's ringing?

["Aidan Williamson" <fluff@xxxxxxx>]

This is a guess as I've nothing to test it with, but could you buy a plug
in
phone ringer & remove the ringer to give a switched input. Would need
to be
one that uses a integral buzzer, rather than an oscillator & buzzer.
Should
only cost a few quid & not need much modding. Depending on the unit
should
get a few volts across 2 pins. Don't know if that would do or if you'd then
need a relay as not familiar with the interface. Sure someone on here could
fill in the blanks. I'd offer to try myself, but have got a bit carried
away
with my spending this week. Maplin have the ringer for ?7.99. Box looks a
reasonable size so might be able to fit relay in if needed to get right
output, or an optoisolator to protect your controller. Might upset BT
though.

Aidan

> -----Original Message-----
> From: Ant Skelton [mailto:ant@xxxxxxx]
> Sent: 05 December 2001 13:52
> To: ukha_d@xxxxxxx
> Subject: Re: [ukha_d] Re: How do I tell whether the phone's ringing?
>
>
> Mark Harrison wrote:
> >
> > Hmmm... really wanted something that didn't involve a PC :-(
>
> You could use a modem plugged in to the phone line. When the phone
> rings, the modem will send "RING RING" out the serial port.
Not sure
> whether you can interface this to homevision, as I don't have one.
>
> My guess would be you either have an rs232 port (in which case you're
> laughing) or a TTL IO pin or somesuch, which might be tricker. To
> interface to that I guess you'd need to knock up a simple little
circuit
> - not sure if that's your bag or not.
>
> Although thinking about it, I don't thing modems send out anything
else
> down the serial port when they're quiescent, so maybe looking for
level
> changes on the modem's serial TX line would be sufficient.
>
> YMMV, HTH etc
>
> ant
> --
>                               /\/\
> ant@xxxxxxx                   (`')                  www.ant.org
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>                     Megawatt Winged Avenger
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