2 Aug
2005
2 Aug
'05
2:42 p.m.
On 8/2/05, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
Having a) looked at competitors features, and b) built similar
products myself, the ones for sale are not simple. Ours used a pair
of SLICs (Subscriber Line ICs) just as a proper PBX or Telco switch
You and I have different ideas of 'simple'. A copuple of SLICs and a
microcontroller is not complicated, at least not compared to many other
projects that I've built, and that I've seen in the magazines, over the
years.
One UK magazine published a design for a telephone exchange. It handled
16 lines, expandable to 32. It was a load of CMOS logic, crosspoint
switch ICs, analogue stuff, etc. No microcontrollers (I think there was
an EPROM to handle the mapping from the telephone number to the
switches), no special SLICs It alloweed several simultaneous connections,
produced dial tone, engagued tone, etc
Surely a 2 line box that produces the right tones and the ringing voltage
would be a lot simpler than that.
-tony
...essentially simulates a telephone
network.... sold by Black Box.
I am surprised, but I have never seen a published schematic for such a
unit, neither in a magaxine or on the web. They can't be _that_
complicated, surely?