First, check both of the modem's speeds. Go to control panel. Click on "Phone and Modem options." Choose the Modem tab. Click the modem and click Properties. Make sure the speed is at about 115,000. You probably wont get much higher even if you tried. You should do this at both points. You may also want to check the "Enable Compression" box. The FCC (I think...) regulated phone line speeds to be no more than 53K.

Next, if that does not help, make sure you have the latest drivers for your product. Make sure to make a system restore point in case something goes wrong.

Also, make sure that his computer is not infected.... You never know what malware can do It can make you BEG for 56K!

You may want to call the phone company and see if what you thought was true, about them limiting speeds. Has he ever connected to a dialup ISP with that same hardware? He should try one if he (or you, I guess...) has a friend around that uses it, just ask to borrow the line while you connect with your father's computer. then you could also try connecting back to your server at the same line. This will help eliminate possible causes.

I probably wouldnt do this, but you can always get yourself some higher speed modems.... 64k and 128k, if you can find them ... Also, if you want to have fun, you could set up directional 2.4GHz satellite antenna thingies... of course you would WPA and password it though

Hope this is of help....