MacTerminal for OS X
Mac OS X has an in-built PPP terminal that can be used to
test a dial-up connection in the same way as a direct COM port session in PC
HyperTerminal.
To run a MacTerminal session, carry out the following
steps...
1) Open the System Preferences application and go
to the Network section
2) Making sure that the Internal Modem port is
active in the Show drop-down box, click the Modem tab
3) Set the Modem drop-down box to Null Modem
115200 (the other options here are not important for this test)
4) Click Apply Now

5) Click into the PPP tab and then select PPP Options...

6) Tick the Connect using a terminal window (command
line) tickbox and click OK
7) Click Apply Now and close the System Preferences
application

8) Launch the Internet Connect application from the
Applications folder (or from the menu bar if you see the phone icon in the
top-right of the screen)
9) Click the Connect button (the modem should NOT dial at
this point)

10) A blank terminal window should open as below...

11) Try to dial out using the standard AT commands as
below (press Return after each command). Change the POP number to match the ISP to which you are making a
connection.

12) When the dial-up process is complete, specify the
username and password (note the password will not be shown)
13) Upon successful authentication, the terminal window
will close...

14) You will be returned to the Internet Connect front
end where the connection status will be confirmed
15) This is now a live connection to the Internet, you
should be able to browse and send & receive mail as normal.

If the terminal connection process works, this should
certainly confirm that all aspects of the hardware are functioning correctly -
perhaps you had previously used an incorrect modem driver in order to make a
connection attempt?
If the terminal connection process fails, there may be a
hardware issue to deal with - for example, a problem with the phone line, modem
cable or the modem itself.