NT 4.0 + broadband

Hi i am new to news groups can someone help???


Want to install BT broadband (business 500) but have discovered that
windows NT is not supported by this system.
We are running Windows Back Office Small Business Server 4.5 on NT 4.0
which does not support USB for the Broadband modem connection. I need
to retain the network systen to enable Microsofe Exchange to route all
inbound mail to the correct locations.     How can I achieve this?

Do I need to update to Windows 2000 server or XP or or ??????

Your help will  be appreciated.


Thanks

Ken Wood