Need Comcast DVR-3 code for Sony MFM-HT95

First, I know this is obvious, but did you already try the codes in the instruction book, and did any keys work (not necessarily the correct function)?

Second, this would be much easier if you have a JP1.2 cable.

If the codes didn't work, and you don't have JP1.2 cable, try assigning code 1232 to the AUX button. It will not work on the TV button (yet), and see if any buttons work. The volume buttons might work, and maybe power and numbers might work. If some thing works, that means 1232 is the correct protocol, and we can go on to assigning the right commands to the correct keys if they are wrong. If not, we'll have to guess another one.