Certainly you could use the telephone line to send
computer data (as in ISDN) to whomever you wanted when you wanted, for the
line was switchable. But ISDN was limited to 64,000 bits per second. If you
needed more bandwidth, you could use the multiplex levels—if you had the
money, but in the United States, you could only get T1 (1.544 megabits per
second) or T3 (44.726 megabits per second) and they weren’t switchable.
