Billion BiPAC 7404V series User Manual page 129

Here are some Examples for your reference:
Main Digit Sequence Lists:
x.
xxx
xxx.
123x.
[x...x]x.
For example: [124]x.
[x-x]x.
For example: [1-3]x.
x[x-x]x.
For example: 9[4-6]8x.
Appendix A: Product Support and Contact Information
VoIP/(802.11g) ADSL2+ (VPN) Firewall Router
Description
Any digit number between 0 and 9 in variable length.
Maximum length is 16.
Any 3 digit number only between 0 and 9.
length is 3.
Note: No period is needed (.)
Any number between 0 and 9 with variable length but
no shorter than 3 digits. Maximum length is 16.
Any number (0-9) starting with 123. Maximum length
is 16.
Any number (0-9) starting with 1 or 2 or 4. Maximum
length is 16.
Any number (0-9) starting with number 1 to 3.
Maximum length is 16.
Any number (0-9) starting with 9, the second number
between 4-6, and third number 8. Maximum length is
16.
Total
128