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Here are questions to test your knowledge of CCNA Voice IIUC topics. These are updated on a regular basis, so keep checking to see more.

When a Cisco IP phone boots up, it requires an IP address to function. The IP address can be manually configured on the phone, but that is a lot of work if you have 240 Cisco IP Phones!

Rather than manual configuration, it is a lot easier to set up a DHCP server on the Cisco Unified Communications Manager router (CME router).

To configure DHCP, do the following:

I have often seen that Digital Signal Processors (DSPs) cause a lot of confusion. Hopefully, the next series of articles will give you the insight to know what they are used for and how to spec them in a router. You will also learn how to configure the DSPs for various functions.

Uses of DSPs:

DSPs are used for the following functions:

• Voice Termination
• Hardware Conferencing
• Transcoding
• Media Termination Points

Before discussing each function, it is important to understand codec complexity.

Here we will continue the discussion talking about transcoding.

How many phones and directory numbers can be configured on Cisco Unified Communications Manager Express by default?

It is important as a CCNA Voice candidate to understand the various codecs that are supported by Cisco IP phones and the bandwidth that they each use.

Various codecs are supported on Cisco IP Phones including:

• G711
• G729
• G729a
• iLBC

Does a VoIP call use 64kbps?

64kbps is the bandwidth of the voice codec when using G711 for example. However, this needs to be encapsulated in IP and other headers.

When converting an analog voice signal to digital, various codecs (coder-decoder algorithms) can be used. The two most common codecs in a Cisco IP telephony environment are G711 and G729 - there are many others, but G711 and G729a (a variant of G729) are supported on Cisco's IP telephony handsets.

Call Manager Express (CME) is a router based VoIP solution currently supporting up to 240 phones. It provides many of the features of Call Manager for a small business.

In this example, I am going to configure 5 phones on my CME system.

CME is based on router IOS. So no need to buy extra hardware - you require a version of IOS that supports CME on a voice enabled Cisco router. You will also need to download the phone firmware and GUI files into flash on the router. CME can be configured directly using the IOS without any other files. However, the phones will use whatever firmware they already have which may not give you the functionality you require.

By default on Cisco Unity Express, when an outside caller leaves a voice mail, CUE will tell the person receiving the voice mail that the call was from an unknown caller.