Modems can be set up in three basic configurations:
A modem connected
to your home computer might be set up to provide dial-out service.
With dial-out service, you can access other computers from your own home.
However, nobody outside can gain access to your machine.
is just the opposite. Dial-in service allows people to access a system from
remote sites. However, it does not permit calls to the outside world.
as the name implies, provides both dial-in and dial-out capabilities.