The dial plan or telephony numbering plan describes how voice calls are routed within the network and explains the site numbering plan and site-to-site dialing instructions. To replace or integrate the legacy PBX systems with the IP telephony systems, you should ask the customer the questions listed in Notes/Comments" section.
3
Has the organization developed a new dial plan for the IPT deployment?
4
Has the organization determined gateway-specific requirements, including protocol-supported and supplementary services (such as call hold, park, and conferencing)?
5
Has the organization determined gateway site-specific requirements such as encoding, calling line ID (CLID), DID support, analog or digital support, and fax relay?
6
Has the organization decided to implement TEHO? If yes, obtain the toll-bypass information in Table C-7.
On-Net Site Access Code
No. of Digits in Station Numbering Plan
DID Ranges
Station DN Numbering Ranges
Station Intercom Numbering Range
Voice-Mail Numbering Range
Current Number of Users
Expected Growth of Users in Next 3 Years
Table C-6. Class of Restrictions Groups
COR Group
Phone Types
Type of Access Granted
COR 1
Assigned to lobby phones
Local calls, emergency calls, toll-free calls, service calls such as directory assistance, and calls to other sites
COR 2
Employee phones
All access given to lobby phones plus long-distance calling
COR 3
Executive phones
All access given to lobby and employee phones plus international dialing
Table C-7. Local Calling Area List for Implementing Toll Bypass
Site Name, PSTN Access Code
DID Extension Range
Local Calling
In-State Toll Calling
In-State Toll Calling
Area Codes/Exchange
Number of Digits Dialing
Area Codes/Exchange
Number of Digits Dialing
Use