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Introducing Cisco Unified Communications System Fundamentals

Chapter Description

This chapter introduces the Cisco unified communications system. To administer Cisco Unity and Cisco PA efficiently and effectively, it is important to have an understanding of the environment they inhabit and operate within. Understanding how calls route through the systems and what you can do with them as they travel is crucial to your ability to administer a Cisco unified communications system.

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Cisco Unity Fundamentals

Cisco Unity Fundamentals


Understanding Unified Communications Integrations

This section describes a Cisco Unity integration, the features it provides, and the basic Cisco Unity integration methods. This section also describes a Cisco PA/Cisco CallManager integration.

It is very important that system administrators of both Cisco Unity and Cisco PA understand how the unified communications servers exchange information with telephone switching equipment. Once you know how Cisco Unity integrates with this equipment, you can troubleshoot problems with it as necessary.

Communications Integration

A communications integration is defined by when a telephone system and the voice-messaging system have a connection between each other, which allows them to send information to each other in a predetermined format. This connection can be a physical one or over a network connection, depending on the systems. In a business environment, when you add a telephone to the telephone system, you need to enter specific information for that new phone, such as the extension that callers dial to reach that phone, the numbers that the user at that extension may dial, forwarding information used when the user is busy or does not answer, and other data. This information is used by the telephone system so that when you call a person, their phone rings and they can answer the call.

The voice-messaging system also uses this information. When you are on the phone and someone calls you, the phone system sends the call to the forwarding destination. In this case, it is the voice-messaging system. When the telephone system sends the call to the voice-messaging system, it also sends information about the person who is calling and the reason the call is being forwarded. After the voice-messaging system receives the call and the information, it can react to the call in the correct way. In this way, when someone calls you at your desk, the call routes to your phone. If you are unavailable, the call then goes to voice mail, giving the caller the opportunity to leave you a message. After the caller leaves a message, the voice-messaging system sends information to the telephone system, telling it to light the lamp on the desk phone.

Figure 1-5 illustrates the type of data sent between the phone system and Cisco Unity.

Figure 5Figure 1-5 Information Sent Between a Phone System and Cisco Unity

Integration Attributes

A Cisco Unity voice-processing system connects to a telephone system, also known as a private branch exchange (PBX), to provide automated attendant, audiotext, and voice-mail service to subscribers. The way in which the systems cooperate and share information determines the level of service that subscribers receive. A telephone system must provide the three following telephone system features for Cisco Unity to qualify the phone system as an integration:

  • Automatic call forward to a personal greeting—Any incoming calls routed to an unanswered or busy extension are automatically forwarded to the subscriber's mailbox in the voice-mail system so that callers can leave a message. This corresponds to arrow 1 in Figure 1-5 and Figure 1-6.

  • Easy message access—The voice-processing system recognizes subscribers when they dial in, saving them from having to enter their personal ID. With this feature, subscribers should set a password on their voice mailbox. This corresponds to arrow 2 in Figure 1-5 and Figure 1-6.

  • MWIs—MWIs alert end users that they have a new message in their voice mailbox. Indicators can be a light on the phone (blinking or steadily lit), a word on the liquid crystal display (LCD) panel of a phone, a message-waiting ring on the phone, or a stutter dial tone. This corresponds to arrow 3 in Figure 1-6.

Figure 1-6 illustrates the attributes of an integration between Cisco Unity and a telephone switch.

Figure 6Figure 1-6 Attributes of an Integration

For more information on the integration between a telephone system and the Cisco Unity system, see Chapter 9, "Cisco Unified Communications Integrations."

Telephone System Integrations with Cisco Unity

The type of integration the telephone system supports determines how the delivery of information between Cisco Unity and the telephone system takes places. The five integration types supported by Cisco Unity 4.0 are as follows:

  • Cisco CallManager

  • Dual-tone multifrequency (DTMF)

  • Simplified Message Desk Interface (SMDI)

  • PBXLink

  • Session Initiation Protocol (SIP)

Each integration is an agreement about the communication protocol and messaging channel to be used. Chapter 9 covers more information regarding how each integration functions, and it also lists the telephone systems that are supported with Cisco Unity.

The information shared between the telephone system and Cisco Unity is the common information that was discussed earlier, in the "Communications Integration" section of this chapter.

Cisco CallManager and Cisco PA Integration

Cisco PA integrates with Cisco CallManager through media points. Cisco CallManager passes calls to Cisco PA through the use of CTI route points. You must build these structures at the Cisco CallManager console.

Figure 1-7 illustrates a Cisco PA/Cisco CallManager integration.

Figure 7Figure 1-7 Cisco PA/Cisco CallManager Integration

When Cisco CallManager receives a call intended for a PA-enabled extension, it first routes the call to Cisco PA. Cisco PA performs a lookup for the user from the corporate directory. The directory must be Lightweight Directory Access Protocol (LDAP)-compliant (Microsoft Exchange 2000 Active Directory or Exchange 5.5 Directory Service).

If the user has routing rules or call forwarding configured, Cisco PA then routes the caller to the appropriate destination through Cisco CallManager.

The destination of the routed call could be a mobile phone, home phone, or any other phone that you can dial from the Cisco CallManager, such as a Cisco IP SoftPhone, Cisco IP Phone, and even Cisco Unity voice mail.


The Cisco IP SoftPhone is a communications application for your laptop PC.

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