When you close your Netscape Communicator 4.x browser, it should bring up a window that tells you “There are open modem connections. Would you like to close them now?”  You can then click Yes to disconnect.  This is a nice feature which avoids a few extra clicks needed to manually disconnect.  You must have an upzip program on your computer, like “Winzip” or similar.  A freeware unzip program called “Expander” can be downloaded by clicking here.