On a full T1, whether it's terminating in a router or switch, the ckt will
be engineered through a 3x1 dacs. This is just to move the ckt off the
carrier DS3 and into the router or switch port. Subordinate slotting is
not supported. The router or switch port would be a full T1 port.
To downgrade the ckt to 256k the T1 must be muxed. A 1x0 or 3x0 dacs port
must be inserted into the T1 path. The four DS0 channels would then be
terminated on a channelized card, like a Cascade 9000 4-port T1 card. All
of this can be pre engineered and a dacs xconnect completed at the time of
cut over to activate the new configuration.
Installing a new loop is a waist of everyone's time and the customers
money. Maybe this is what Sprint had in mind. The customer would incur
additional install charges and probably dual ckt payments for about a
month.
Todd