i am interested in the design of an alarm interface to a communications system and was hoping you could help.
What my proposed system is meant to do is recieve an alarm alert and convert this to a text message then send it as an email to a specific computer(s).
I figure i would be using a point to point protocol as the email pathway, but am having a bit of trouble designing the circuit, I think that the best way to get an initial system up and running would
be through the use of maybe a mircocontroller and a modem attached.  Inputs
to the unit from the home sensors would come in via the serial port.  (We
would have a custom microcontroller monitoring your sensors or other
inputs(s) and relaying this data to the single-board computer via the serial
port.)  and a program would start that monitored the serial port.  When emergency conditions are
met, a program would start running that performed an auto-dial and login to
a local internet service provider.  Once this connection is established, the
program will send an e-mail indicating the problem and perhaps what sensors
had been activated, and then it will log off.
Any pointers on the circuitry design would be greatly appreciated.
I would like to thank you for your time
Yours
A.Ibrahim
aimx@hotmail.com