Avaya Communication Manager Administrator's Manual page 1354

Screen Reference
Ext Len
Specifies the number of digits the extension can have. On page 1, this field displays the
extension length entered as a qualifier on the command line (change
public-unknown-numbering n).
Valid entries
0 to 7 or blank
Total CPN Len
Valid entries
0 to 15 or blank
Trk Grp(s)
Communication Manager generates the station's identification number if there is an entry in the
Ext Code field, and this field is administered with the trunk group number carrying the call.
Valid entries
1 to 7 digits
blank
1354 Administrator Guide for Avaya Communication Manager
Usage
Corresponds to the extension lengths allowed by the dial plan.
Usage
Enter the total number of digits to send.
Usage
Enter the valid administered ISDN trunk-group number or a range of
group numbers. For example, if trunk groups 10 through 24 use the same
CPN Prefix, enter 10 to 24.
The identification numbers are not dependent on which trunk group the
call is carried.