Trouble maintaining connection with 56K modem

First off, no, you have not just entered a time stream vortex, bringing you back to you back to 1998. The year is still 2013 and I'm hoping I can get some help for my mother's ancient computer, running on Win XP, with a dial-up connection.

Her modem keep dropping connection. It'll dial up and connect just fine, but within seconds (some times minutes) the connection is dropped and it automatically redials, just to have the same thing happen over and over. According to her, this is not the first time this has happened. When she first moved into her rural area home, she had the same issue with her previous computer. Apparently, she had someone there who was able to 'enter a code' to tell the modem to ignore static on the line, and maintain connection. He made it sound like he was some super genius, and that even the ISP tech guys didn't know about this little trick.

I'm assuming it was some sort of DOS command, or something..? Is there anything you can tell me here, without me knowing any of the modem specs? I'll be house sitting for her next month, and I would really like to figure out what the problem is, before being stranded without any internet whatsoever.

 

After a little searching yesterday, I found this: http://www.usr.com/support/756/756-ug/six.html I think this could hold the key to my issue...but I have no idea which command I would use, or even how to get to the right spot to input the right command...help? :\