the rotary phone project got me thinking about how cheap it is to add an extra sim card on an existing family plan (something like $10/month). but, instead of just one old rotary phone in use around the home, i’d like to run all the regular consumer POTS phones all around the house.
the very basic system would be something that generated a dial tone, ring in, some way to deal with multiple pick ups (maybe just an impedance strategy) and that’s about it. once that was working, the next (possible) step would be caller id. if all that was solid, then maybe there would be room to try to work out the GPS standards for emergency calls so that a 911 would bring the trucks to the right house (this might just be something that can be worked out with the billing address and the cell provider, not sure).
in any event, a land line is costing us about $70/month. not counting the hours put into the prototype, the system pays for itself somewhere between 8 and 12 months after install.
the system could easily be powered off the existing POTS lines, but that would be illegal, i believe. the optimum plan would be for mains power so that the whole thing could be run off of a consumer UPS. with these types of current draws, a $50 UPS could last days.
i’m looking into ASTRISK pbx to see if it could make things easier (though i’d rather not have to run a whole PC to get this running).
I’ve searched online and found exactly (seemingly) the same device here: http://www.rfwel.com/shop/product.php?productid=1064
but i wouldn’t mind trying to make one.
does anyone think this might be a good idea?