controller E1 0/0/0
ds0-group 0 timeslots 1-4 type r2-digital r2-semi-compelled ani
cas-custom 0
dnis-digits min 3 max 11
ani-digits min 1 max 65

dnis-digits min 3 max 11
If dialed digits maximum is not known, cas has to rely on a timeout
(3 seconds by default). If max is known then cas will gain 3 seconds
in inter digit timeout.

ani-digits min 1 max 65
A minimum of 1 means there should be at least one digit in the
ani of the incoming call.