[cisco-voip] Types of PRIs: "Voice", "Voice, Video and Data", "Unrestricted Digital"

[Vance Shipley]

It's unfortunate that the telcos make this so difficult that
everyone is really confused on what is a simple point.  When
you place a call with ISDN a description of the bearer service
required for the call is included.  If "Speech" is requested 
the telco(s) handling the call may use echo cancellation,
compression, etc. whereas if you asked for "56K data" or "64K
unrestricted" they must not.  That's the basic technical issue.
Everything else is telco tariff madness.

	-Vance