No answer from dial-up connection.

[Zaster Sap]

I'm trying to set up dial-up access to a WinXP Pro
machine on a LAN at our office. It is a small LAN
and all I know about our internet connection is that
it is through a Verizon DSL modem. We also have
a ZoneAlarm firewall running on the XP machine.

I enabled dial-up access on the office machine by
setting up an "Accept incoming connections" entry
in my network connections. I did not allow VPN
connections. I followed the instructions I found
in a WinXPPro book and the setup seemed successful.

But when I attempted to dial in from my home
(WinNT 4.0) machine, my machine dials the number,
I hear what sounds like four rings, then two beeps,
then silence. Then I get an error message saying
that there is no answer from the other end. I'm sure
I'm using the phone number.

Before I get into details of parameters I would like
to know if there are any basic pieces of the puzzle
that I have left out, like for example do I have to
do anything with the DSL modem to allow incoming
calls?

Is there anything else I have to do on the WinXpPro
machine to get Remote Access Server working?

Could the firewall be keeping me out?

Any ideas?

Thanks in advance.