Software based Caller ID project- Problem with getting caller ID signal
Two of the line look like they will carry the signal that you're after, the ones that connect to the topr-right corner of the IC with the series resistor and capacitor, but you cannot/shouldn't connect them straight to you PC without:


knowing the expected signal levels of the signal you are interested in, the inputs must happily accept the signal levels;
protect the input against ring voltage, which can be up to several 100's volts peak to peak;
protect against overvoltage as a result of eg. lightning in the neighbourhood;
an insulation transformer for galvanic separation of the phone line/PC. (You can often find those in old modems or telephone sets.