I will take a wild guess, and imagine that you want to connect a computer to the Denon so that you can send control commands from the laptop to the Denon. To do that, all you need is a serial cable. It is possible that you might also need a "null modem adaptor" at one end of the serial cable.
If you were hoping to send audio or video, the serial cable is not going to do that.
And...of course you will need some kind of software on the laptop to communicate with the Denon. Can't help much there...it could be simple, or somewhat tricky. for example: good old Sony laserdisk used the command "OP" to open the laserdisk tray, and "PL" to play the disk. Nice, easy. Some other gear I had needed a convoluted bunch of cryptic numbers to do the simplest thing.
hope that helps some...