You need a modem router like the 3Com OfficeConnect 3C888US. They're about $300, and there may be some that are cheaper. If you have a dial-up server (or can configure one) at the home office you can have the remote office dial right in. I don't think there's a way to make an NT workstation box act as a router to a dial-up. If you give your new modem router the same IP address as your T1 firewall/gateway then you don't have to reconfigure any of the client machines. I don't have this model (rather an old WebRamp), but they are very simple to set up, a consideration if you don't have skilled personnell at the remote site.

If the NT boxen were getting security authorization from the home office over the T1 then I might think about configuring the Domain server for slow links.

-Zeke

That, or install Linux on your NT Workstation box!