Another update; so I've moved forward on the PIC chip version of this board to bring the parts count down, and can probably make this available to people as pre-assembled boards, as there's many folks who seem to want one of these. NOT YET, as I'm still in development, and not even quite ready for alpha testing yet.
So a temporary progress page on this new PIC chip version of the board is here:
http://seriss.com/people/erco/tmp/pic/It looks much like the 'all discrete' version, but with many less resistors/caps, and no LM339's.
The board is also a little smaller, and cheaper to print now that I got away from the other software I'd been using.
With this new software, I can have the boards printed for about 1/3 the cost, or less! And with the extra room freed up
by the lower parts count, was able to mount the large transistors flat to the board so they don't flop around. (Metal fatigue
of the transistor pins was a concern when mounted vertically, so this is much more structurally sound)
I went through a 'round of printing these new PIC boards, and just today finished writing the software firmware
for the PIC chip that handles all the logic of those LM339/analog circuits did.
I'll update the above page with that firmware code later today, for anyone interested in PIC chip software.
The PIC chip model I'm using here (there's many, many models by the way), the one I'm using here is a PIC16F1709,
a 20 pin chip that has the exact number of I/O signals I need for this project (which is 17).
I also bought an XLink, a cool little ~$60 box that acts as a bluetooth gateway between a cell phone and a land line.
It was an easy one-button setup, and an easy way to get your old phones to ring and make calls over a cell phone.
I could see multiple cell phones appearing as separate lines on a 1A2 system, for instance. Worked fine for me;
it gives a fake dial tone when you pickup, and uses the touchtones to make the call. I'm not sure how it knows when
you're done dialing to initiate the call, but it does work for the normal US numbers I've dialed. (1+areacode+7 diigts).
I made sure the new board can work with that device, as it's probably typical of IP phones as well; the ring
voltages are slightly different (lower voltage) than most CO's, just enough to ring a regular model 2500.
So I adjusted my ring detect circuit to make sure it properly detects ringing for that lower voltage too.
Anyway, at some poin, when I'm ready for testing, it'd be great if I could send a test board
to one of the mods
of this BBS (who lives in the continental US) to try out for testing/feedback purposes. I know it's only
about $25 to send these boards through the US post using one of their standard priority mail boxes.
So I could send you one to try out, and then you can mail it back to me when done testing.
