I have a land phone that displays the caller ID. I want to use a some interface or cable to connect the phone to a pc and then connect it to mysql, check if the user is available in the database, and if not, I add him, (name, number, location)
closed as not a real question by Nifle, Simon Sheehan, ChrisF, RedGrittyBrick, Dave M Feb 10 '12 at 13:21
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Taking the information from your question, I tend to think that a custom-built system consisting of Asterisk PBX and a custom-written software that can query a MySQL database from Asterisk can help you.
The telephone line that you are going to use should probably support the CallerID functionality.