Line Load Control (LLC) is a feature that restricts a predefined set of telephone users from originating calls during a crisis or an emergency. LLC systematically reduces the number of telephones that can originate calls during high-traffic periods. This situation is sometimes called a lockdown. When the lockdown situation passes, the LLC restriction levels can be reduced or removed completely.

Users are assigned to a Line Load Control level based on the relative importance of the position of the user within the organization. When an emergency occurs, the administrator manually activates the LLC feature to restrict calls by users with positions that are of lower importance. When the emergency is over, the administrator manually disables the LLC feature.

For example, if a security emergency occurs, telephone users who are responsible for managing the crisis are unrestricted from originating calls. Other telephone users, for example, users in the accounting department, are restricted. When the crisis is over, the administrator returns the system to normal operation.

The LLC feature can be controlled at four levels. These levels determine what telephones, based on the Class of Restriction (COR), are restricted from originating calls. This feature does not restrict incoming calls, or calls that originate from an attendant console or a night telephone.

The four levels are as follows:

Level	Definition
0	The LLC feature is inactive, that is, no restrictions exist. This is the default setting.
2	Restrict telephones with a COR that is assigned to LLC levels 2, 3, and 4.
3	Restrict telephones with a COR that is assigned to LLC levels 3 and 4.
4	Restrict telephones with a COR that is assigned to LLC level 4.

System level 1 is an invalid value. The LLC feature cannot restrict telephones with a COR that is assigned to LLC level 1 from originating calls.

When LLC is activated, the system restricts all telephones with a COR at that LLC level and below from originating any calls. If a restricted telephone is already active on a call when the restriction is activated, the call is neither interrupted nor disconnected. The telephone becomes restricted only after the user hangs up from the active call.

When the need for LLC has passed, the administrator can change the LLC to a less-restrictive level, or completely deactivate the feature.

The following table shows how the LLC feature can be used.

Extension	COR	LLC Level
5300	11	0
5350	12	2
2540	13	3
3300	14	4
2635	14	4

For this example, the LLC is at Level 0, and extension 2635 is active on a call.

1. Because of high telephone traffic, the system administrator changes the LLC to level 3.

   Extensions 2635, 2540, and 3300 cannot originate calls because the assigned COR LLC level for these extensions is equal to or less than the system LLC level.

   The active call on extension 2635 is undisturbed. As soon as extension 2635 disconnects, this extension cannot originate calls.

   Extensions 5300 and 5350 can originate calls because the assigned COR LLC level of these extensions is higher than the system LLC level.

2. Call traffic is still too high, so the system administrator changes the LLC to level 2.

   Now extension 5350, in addition to extensions 2635, 2540, and 3300, cannot originate new calls. Extension 5300 can still originate new calls.

3. Call traffic subsides. The system administrator changes the LLC back to level 0.

   All extensions can now originate calls.