Selecting Features for IP Phones

The maturity of PBXs allows them to offer a suite of user features. To compete with a PBX, an IP telephony solution must offer comparable features. Fortunately, the Cisco CallManager platform offers most any feature found in today's modern PBXs, and a few features not found. This section introduces you to a sampling of the many features available in CallManager 4.x platforms.


A conference call allows multiple parties to simultaneously speak with each other. The processing of mixing together different audio streams can put a strain on a CCM server's resources. Therefore, some network designers dedicate a CCM to conference call support. A dedicated CCM server supports up to 128 users in a single conference call. For enhanced scalability and to reduce the conference call processing burden on the CCM server, hardware installed in various Cisco routers and switches can offload the conference call processing, making hardware conferencing the widely preferred method.


The Annunciator plays prerecorded announcements (for example, a .WAV file) to give callers information about why a call failed. For example, during a service interruption, a caller might hear, "A service disruption has prevented the completion of your call. In case of emergency, call your operator. This is a recording."


Transcoding resources (for example, DSP stored in Cisco routers or switches) convert back and forth between high-bandwidth CODECs (for example, G.711) and low-bandwidth CODECs (for example, G.729). Therefore, a call originating as a G.711 call could be converted into a G.729 call before going across a WAN connection. Such a resource might be needed if you have equipment (for example, an interactive voice response system) that only supports the G.711 CODEC, and you simultaneously want to use the G.729 CODEC over the IP WAN (for bandwidth preservation).

Music on Hold

When a caller is placed on hold, is being transferred, or is being conferenced in with another party, the CCM software can play music on hold (MOH) for the listener. CCM administrators can easily add MOH files by dragging and dropping either .WAV or .MP3 files into a designated folder on a CCM server (assuming the administrators have the licensing to do so).


Some Cisco routers have the ability to play MOH, thus eliminating the need for MOH traffic to cross the WAN.

Speed Dial and Abbreviated Dial

A speed dial button allows a caller to press a single button to reach a preconfigured destination. For example, you might have your "significant other's" phone number programmed in as one of your speed dial buttons. However, depending on a caller's IP phone model, the caller might need additional speed dials. Therefore, Cisco allows the administrator or the user to configure abbreviated dial numbers.

A Cisco IP Phone supports up to 99 speed dial entries, and users can enter a one- or two-digit number (that is, the abbreviated dial number) and then press the ABBRDIAL softkey to dial a preconfigured abbreviated dial number. For example, imagine you entered your dentist's phone number in your IP phone's 49th speed dial entry. Because your IP phone doesn't have 49 speed dial buttons, you dial 49 and then press the ABBRDIAL button to call your dentist. Keep in mind that the phone does not permit you to scroll through your abbreviated dial numbers, which is one drawback of abbreviated dial.

Auto Answer

The auto answer feature allows a phone to answer a call as soon as the call comes in. This feature might be useful for a call center environment, where customer service agents wear headsets and can start talking with an incoming caller immediately, without having to reach for the handset.

The CCM administrator can configure the auto answer feature to auto answer using either a headset or the built-in speakerphone, which brings to mind another possible application. If you have a Cisco IP Phone in your home, and you leave your teenage children alone for the weekend with the instruction not to have any parties, you could call your phone remotely. The IP phone, configured for auto answer, immediately answers using the speakerphone, and you listen in on what's happening in your home.

Call Forward

When you are in a meeting or away from your office, you might want your calls forwarded to voice mail or another phone number. The CCM supports three call- forwarding types: 1) Forward All (all calls forwarded), 2) Forward Busy (calls forwarded when you're on the phone), and 3) Forward No Answer (calls forwarded if you don't answer your phone after four rings).

Direct Transfer

The Direct Transfer feature allows you to join two parties together. Perhaps you have someone on hold, and you are talking with someone else. Pressing the DirTrfr softkey joins those parties together, without consuming any conferencing resources.

Call Join

Whereas the Direct Transfer featured allows you to join two calls, the Call Join feature allows you to join up to 15 active calls, in addition to yourself, in a conference call. The person who initiated the call, however, is the only person allowed to add participants to a call. The conference call remains active even if the call originator hangs up.

Immediate Divert to Voice Mail

The Immediate Divert (iDivert) softkey sends a call directly to voice mail. For example, you might be meeting with someone in your office, and your phone starts ringing. You don't want to disrupt your meeting by answering the phone, and you don't want to allow the phone to ring four times before the incoming calls are forwarded to voice mail. Pressing the iDivert softkey immediately forwards the incoming call to voice mail, minimizing the disruption to your meeting.

Multilevel Precedence and Preemption

Multilevel Precedence and Preemption allows high-priority calls from authenticated users to preempt lower-priority calls. For example, a national emergency might flood a company's phone system with calls. With Multilevel Precedence and Preemption, administrators assign designated users priority over any existing calls to, for example, coordinate emergency responses.

Malicious Call Identification

Users receiving malicious calls can press the Malicious Call Identification (MCID) softkey (or dial a feature code) to send an alarm notification to the CCM administrator. The MCID feature also flags malicious calls in the call accounting records and can send special messages to the primary rate interface (PRI) to hold the call up, allowing authorities to trace the call back to the originator.

Call Park

Call Park allows a caller to "park" a call in a location identified by a number. The parked call is retrievable from another phone. From the other phone, simply dial the number identifying the parked location to retrieve the call.

Call Pickup/Group Call Pickup

Consider a group of workers in the same department working in neighboring cubicles. These workers might need the ability to answer a call coming into a coworker's phone. This function is supported by the Call Pickup feature. The Group Call Pickup feature extends the ability of the Call Pickup feature, allowing a user to answer a call coming into another department's phone. For example, perhaps a receptionist serves both the accounting and payroll offices. The Group Call Pickup feature allows the receptionist to answer an incoming call for either of these call groups.

Call Back

When I call my mother from my home phone, if her line is busy, I hear a message from my local phone company saying they can notify me when her phone is no longer busy (for the low, low cost of 90 cents!) The Cisco CallManager Call Back feature offers a similar function for on-cluster calls (without the 90-cent charge).

Barge and Privacy

Did you ever call a company and hear a message similar to, "This call might be monitored for quality assurance"? The CCM software supports the ability for someone else to join a call (and perhaps monitor the call for quality assurance) with the Barge feature. However, there might be times when you don't want your boss barging in on your conversation. Perhaps you don't want someone listening when you're talking with your spouse, or worse yet, listening in on a phone interview with another company! The Privacy feature allows a user to prevent anyone from barging into a call, on a call-by-call basis.

Voice over IP First-Step
Voice over IP First-Step
ISBN: 1587201569
EAN: 2147483647
Year: 2005
Pages: 138
Authors: Kevin Wallace

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