On Thu, 10 Aug 2006 01:29:15 -0400, "Dave Soemarko"
<fotodave@dsoemarko.us> said:
> Actually the circuitry of the phone company does the decoding. The rotary
> phone does not convert the dialed number into dial tone. It simply breaks
> the line on and off, and the phone company counts the number of ons and
> offs
> and decode the number (The phone company added this intelligence in their
> system when they convert all lines to dial-tone decades ago because there
> were still many rotary phones around).
In some parts of the world, phone company may charge extra for dial or
tone dialing. I don't know how it's like now, even in my region. (I've
been landline-free since 1998.)
Besides, if I can't send DTMF, it's practically useless because most of
the time I need to use landline is to call banks, UPS, FedEx, and other
companies.
Yes I know I can dial by manual pulsing. The number for line testing
is/was often 111 or 121 or something very easy to dial by hand. But I'd
rather program a PIC and let a relay do the job. Or maybe I use a punch
card and a photointerrupter so that I can "program" the numbers I call
frequently...
Received on 08/10/06-12:09:25 AM Z
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