Do you mean via an Internet fax service? If so, it depends on how the
service works. If it expects you to send an e-mail, you have to send the
doc. as an e-mail (or maybe an e-mail attachment). If it expects you to
print to a virtual fax printer, you should be able to print like you would
to a traditional fax printer.

If there is some type of "DSL service" that isn't an Internet service, I
have no idea what the answer might be.

Peter Jamieson

You can set up microsoft fax and use it just like you would a printer.  You
select print and choose the fax driver for the printer type.  Make sure the
phone number and setup protocalls have been installed.