6. Numbering plan restriction (AN/TTC-30). If an AN/TTC-30 is included in the circuit switched
network and the planner desires to provide the subscriber automatic access to the network, a number of
restrictions are encountered. They are-
a. Restriction of SL codes from 50 through 99 (except 54 and 67).
b. Restriction of subscriber codes 102 through 499 (numbers 100 and 101 are reserved for operator
7. If the AN/TTC-30 subscribers are to have automatic access to all members of the network, all other
switches in the network must adhere to e restrictions. If the AN/TTC-30 is connected to an AN/TTC-
39/39A, the AN/TTC-30 subscriber cannot dial SL-000 and reach the AN/TTC-39/93A operator.