These were popular in the day to connect small offices to the net... it combined a mini file server, served as the wan link, mail, etc... These particular 2 units have the sync card and cable for an external CSU/DSU. If there is any interest, fire over an offer... I won't be doing anything with them and they are taking up space... I have one new unit and one demo unit both in their original box with docs and csu/dsu cable. -- Curt