E.g, where a non-clear channel digital path exists from the customer's
ISDN CPE to the PM3, it is technically possible to accept a 56K data
or DOSBS call the same way you would if your line was PRI.
Where PRI service is inordinately expensive, this can be a good option to
give users who have ISDN inexpensive digital dialin access, with only a
small loss in throughput.
I've confirmed that the Ascend MAX does this, if that's any incentive...