To configure the Dial Plan Features, click Account—Advanced—Dian Plan. 

1. Accept Digits:

1,2,3,4,5,6,7,8,9,0,*,#

2. Grammar:

3. Examples:

Example 1: 
{[369]11 | 1617xxxxxxx} :
Allow 311, 611, 911, and any 10 digit numbers of leading digits 1617 

Example 2: 
{^1900x+ | <=1617>xxxxxxx}:
Block any number of leading digits 1900 and add prefix 1617 for any dialed 7 digit numbers 

Example 3: 
{1xxx[2-9]xxxxxx | <2=011>x+}:
Allow any length of number with leading digit 2 and 10 digit-numbers of leading digit 1 and leading exchange number between 2 and 9; If leading digit is 2, replace leading digit 2 with 011 before dialing 

Example 4: 
{99,x+|[*x]+}:
When user dial 99, can hear dial tone again, user continue dial, dial tone will stop 

Example 5: 
{0xxxxxxx}:

Only 8 digits starting from 0 can be dialed.

4. Default: 

{[x*]+}