Lets come back to dialup later. Lets have some basics first - the first thing you should be asking yourself is how many network cards you have. Lets say you have two LAN cards(or lets say 1 WAN card and 1 LAN card, typical scenario) and both of these can be connected to internet. I am assuming you are on
windows.
- You could install a virtual machine e.g. VirtualBox, VMWare player. These would allow you use any of these two cards as network provider for your virtual machine. Now your base machine uses LAN card 1 and virtual machine uses LAN card 2. Simple and easy.
The reason i recommended a virtual machine approach is that when you have talk about combining two connections on single OS, you are talking about dynamically routing your packets to either of card based on some criteria. You have to make sure that your routing tables are configured in such a way that one card handles traffic to a certain IP range and other one handles a different IP range which can be difficult but its possible.
As a POC, i did once combine a wireless connection with an ethernet connection. But that was done on linux. Its a little technical, as I told you have to manually configure your routing tables. Just in case you want to have a look, its
here.
If you want to achieve this on windows you would like to go the Wingate way. I have not tried this, but
this link might be useful.
