Steve is right: the two types of signal are different and there is no splicable solution....Assuming that its not some proprietary format, with some help, it can be done with dedicated circuitry to convert an analog (RCA) signal to a digital one. (USB). You should be able to buy an RCA to headphone jack cable, and then a USB microphone with an audio in input. ($3 dollars for cables off amazon + $20 for a mic. http://www.amazon.com/Griffin-Technology-iMic-Audio-Device/dp/B000BVV2IC/ref=sr_1_1?s=electronics&ie=UTF8&qid=1358715231&sr=1-1&keywords=USB+microphone+line+in & cable like http://www.amazon.com/3-5mm-Stereo-Female-Cable-inches/dp/B0018MI5F6/ref=sr_1_10?ie=UTF8&qid=1358715461&sr=8-10&keywords=RCA+cable+convert ). You may be able to do better pricing. These are just the first I saw...Alternatively, you might have a microphone jack on you computer and be able to use the above mentioned converter cable, bypassing USB entirely.Good luck.