# Object: Internal Number

The **Internal Number** object is used for internal dialing as an
extension number. This facility allows users to call each other directly
and to reach selected objects (such as **Conference** and **Voice Menu**
objects) via internally-assigned extension numbers. Note that one
**Internal Number** object must be created for each internal extension
required, and extension numbers cannot be duplicated on multiple
**Internal Number** objects.

Internal numbers are optionally used as internal caller IDs by
SIP devices when making outbound calls to other extensions within the
phone.systems(TM) network.

![../../../_images/internal-number-object.jpg](../../../_images/internal-number-object.jpg)


**Fig. 1.** Internal Number Object

The information to be entered for this object is:

- The name of the **Internal Number** object, for example, "Sales Conf
  Extension".

  Newly created **Internal Number** objects are automatically assigned default names in the format {Tab name} {Object
type} {Object type count in current tab}, such as "Main Internal Number 7."
- **Internal Number (Extension Number)** This is the number used for internal dialing (1 to 4 digits). It can be selected from a list of unused internal numbers that were previously added in the [Internal Numbers](../../Numbers/internal-numbers.html#ps3-internal-numbers) menu.

![../../../_images/fig136.png](../../../_images/fig136.png)


**Fig. 2.** Internal Number Object Creation

A simple usage example of the **Internal Number** object is shown below,
where an internal extension number is dialed by phone.systems(TM) users to
access the company's conferencing facility.

![../../../_images/internal-number-example.jpg](../../../_images/internal-number-example.jpg)


**Fig. 3.** Example