SG-S3 = Samsung Galaxy S3

Fact= S3 has no built in IR (infrared) needed to be used as a Universal Remote, in my case to work with my Sony Amplifier model STR-DH100

I suceeded using my S3 phone TODAY to do many things on my PC wirelessly : moving the mouse, using chrome, controlling foobar2000 by a server. It is basically awesome.

NOW.

Can my PC be used as a tool for my S3 to work with my Sony AMP? In some way...

ThanksIt TOTALLY depends on the model of amplifier. Some higher end models have a serial/RS232 port on the rear which you can use to send control commands to it. If yours has this then it is certainly possible to control the receiver from the PC and therefore your phone however you would more than likely have to build custom software to do this, it would be much easier to just get a universal remote

I have DONE this before with my Cambridge Audio receiver - I GOT it used without a remote and while I can control everything I usually need from the front panel I needed to change one setting (Subwoofer crossover frequency) which required the remote. In the end I was able to hook an old laptop up to the serial port and send the commands down to EFFECTIVELY emulate the remote control in order to navigate the menu and set the appropriate settings.I have a DM PORT (DC5V) is it for wireless connections?That's for connecting mobile devices such as phones to the amplifier to play sound over it, not for connecting to a PC.

To be clear, are you definitely wanting to control it from your phone or do you simply not have a regular remote for the amplifier in which case why not just buy a universal remote?I already have a Universal Remote.
I am just trying to learn all the limits that the S3 can or can't break through.Well, once you have the S3 talking to a computer then there is really no limit to what you can control with it, it's just a matter of how complicated or time consuming the setup would be.