ISDN专线是不能访问因特网的吧

hppyhjh

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.

考虑对于ISDN租用专线的情况, 它是无交换的, (they weren't switchable)
那么这种情况下, ISDN类似于点对点传输, 它的的应用场合只能是比如分公司与母公司之间的线路连接
等等这些情况吧, 用ISDN专线来访问internet,那是不可能的,对吧...因为没有人给你提供路由