Drag, Drop... Done

According to Tivey, the only drawback of ISDN for point-to-point communications is that transmission is dependent on "both transmission ends being able to transfer, staying in contact with each other during transfer and being compatible in technology."

In other words, both the sending and receiving parties must have ISDN, and the line has to be available for transmission—as opposed to Vio's managed network or even the Internet, where users can connect via a variety of means, and files can be uploaded to and downloaded from a central server at the users' convenience. But these issues can be offset by the decreasing cost and increasing ease of ISDN.