Configures the DSU Module for the specific type of network
being used.
dds - AT&T's Dataphone Digital Service, generically known
as Digital Data System. Requires 4-Wire interface.
att - AT&T's Switched 56 Network. Operates over 2-Wire or
or 4-Wire interface.
sprint - Sprint Switched 56 Network. Operates over 2-Wire or
4-Wire interface.
otherCarrier - Other carrier being used.