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Cisco Unified IP Phone Administration Guide for Cisco Unified CallManager 5.1 (SIP), Cisco Unified IP Phones
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Chapter1 An Overview of the Cisco Unified IP Phone
Overview of Configuring and Installing Cisco UnifiedIP Phones

Security Restrictions

A user cannot barge into an encrypted call if the phone that is used to barge is not
configured for encryption. When barge fails in this case, a reorder tone (fast busy
tone) plays on the phone on which the user initiated the barge.
If the initiator phone is configured for encryption, the barge initiator can barge
into an authenticated or nonsecure call from the encrypted phone. After the barge
occurs, Cisco Unified CallManager classifies the call as nonsecure.
If the initiator phone is configured for encryption, the barge initiator can barge
into an encrypted call, and the phone indicates that the call is encrypted.
A user can barge into an authenticated call, even if the phone that is used to barge
is nonsecure. The authentication icon continues to appear on the authenticated
devices in the call, even if the initiator phone does not support security.
Overview of Configuring and Installing Cisco Unified IP Phones
When deploying a new IP telephony system, system administrators and network
administrators must complete several initial configuration tasks to prepare the
network for IPtelephony service. For information and a checklist for setting up
and configuring a complete Cisco IP telephony network, refer to the “System
Configuration Overview” chapter in Cisco Unified CallManager System Guide.
After you have set up the IP telephony system and configured system-wide
features in Cisco Unified CallManager, you can add IP phones to the system.
The following topics provide an overview of procedures for adding
Cisco UnifiedIP Phones to your network:
•Configuring Cisco Unified IP Phones in Cisco Unified CallManager,
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•Installing Cisco Unified IP Phones, page1-26