[Required: TS, EOS, SMEO, MFS, PBX1] Ten-digit dialing shall consist of using 10 digits comprising the area code, switch code, and line number to establish inter-switch calls where the number plan area of the calling party is different from the number plan area of the called party. Number assignments for this plan shall be of the form KXX-KXX-XXXX, where K is any digit 2-8, and X is any digit 0-9. DSN ROUTINE 10-digit inter-switch calls are initiated by dialing the appropriate sequence of (1X) KXX-KXX-XXXX or 94 (1X) KXX-KXX-XXXX. DSN calls above ROUTINE precedence are initiated by the appropriate sequence of 9P (1X) KXX- KXX-XXXX where P is the precedence digit (0, 1, 2, or 3). Access to other Government and/or commercial services is obtained by dialing 9 followed by the appropriate service digit(s).

For example, please refer to OpenScape 4000 V8, Volume 1: AMO Descriptions, Service Documentation, chapter WABE - Digit Analysis.