Customer (Single- or Multi-Site) Without PSTN Prefix
----------------------------------------------------

Most of the calls made by these customers are PSTN calls. The Cisco Unified
Communications Manager interprets calls without any prefix as PSTN or off-net
calls. To differentiate between PSTN and intra- or inter-site calls, a prefix is
required.

Single or Multi-Site Customer without PSTN Prefix

+--------------+---------------------+--------------+-------------------+
|              | Dialing Format      | Display      | Notes             |
|              | (A-Party)           | Format       |                   |
|              |                     | (B-Party)    |                   |
+==============+=====================+==============+===================+
| Intra-Site   | * Extension Prefix  | * Extension  | Since any digit   |
| Dialing      |   + Extension (for  |   Prefix +   | 0-9 is treated as |
| (single site |   example, \*4321)  |   Extension  | a PSTN call,      |
| only)        |                     |              | extension prefix  |
|              |                     |              | or ISP is limited |
|              |                     |              | to only * or #.   |
|              |                     |              | For a single site |
|              |                     |              | customer, the     |
|              |                     |              | dialing plan for  |
|              |                     |              | intra-site calls  |
|              |                     |              | is just an        |
|              |                     |              | extension prefix  |
|              |                     |              | + extension.      |
+--------------+---------------------+--------------+-------------------+
| Intra-Site   | ISP + Site Code +   |              | For a multi-site  |
| and          | Extension (for      |              | customer, it is   |
| Inter-Site   | example, \*2551234) |              | recommended that  |
| Dialing      |                     |              | extension dialing |
| (Multi-Site) |                     |              | is not supported  |
|              |                     |              | and all calls are |
|              |                     |              | dialed as ISP +   |
|              |                     |              | Site Code +       |
|              |                     |              | Extension.        |
|              |                     |              |                   |
|              |                     |              | Note:             |
|              |                     |              |                   |
|              |                     |              | ISP must not      |
|              |                     |              | conflict with     |
|              |                     |              | PSTN dialing and  |
|              |                     |              | is therefore      |
|              |                     |              | limited to * or #.|
+--------------+---------------------+--------------+-------------------+
| PSTN Dialing | * PSTN Number (for  | * NN         | There are several |
|              |   example,          | * Local      | alternatives for  |
|              |   19197221234       |   Number     | display. Some of  |
|              | * E.164 Number      | * E.164      | the phones support|
|              |   (for example,     |   Number     | E.164 dialing     |
|              |   +19728134321      |   (+CC NN)   | (including + sign |
|              |                     |              | Some customers    |
|              |                     |              | prefer to display |
|              |                     |              | the number as it  |
|              |                     |              | would be dialed.  |
+--------------+---------------------+--------------+-------------------+
| DN Format    | * Extension(Single  |              |                   |
|              |   Site) (for        |              |                   |
|              |   example, 4321)    |              |                   |
|              | * Site Code +       |              |                   |
|              |   Extension         |              |                   |
|              |   (Multi-Site)      |              |                   |
|              |   (for example,     |              |                   |
|              |   2554321)          |              |                   |
+--------------+---------------------+--------------+-------------------+