lows caller ID information to be sent to the phones. The connection plar command forwards incoming calls to extension 111. Notice that I haven't specified the line's phone number anywhere. It's not needed, but to keep things clear, we can label the port with a description: R1-PBX(config-voiceport)#description 555-123-4567 Chances are, in a corporate environment, you're more likely to have a PRIT1 installed. Small offices, like the one used in this chapter's examples, don't have the need for 24 lines, SO they may still use POTS lines. Configuring Phones There are two major steps to configuring the buttons on your phones. There are many things that Cisco IP phones can do, but at a minimum, users will need to be able to pick up a line and make a call. The lines on a phone are tied to the phone's buttons. Phones have a lot of buttons, but the buttons on the right side of the Cisco phone's display (line keys in Cisco parlance) are the ones to which I am referring. Generally, these buttons are assigned to a phone extension, which is an ephone-DN in our con- figuration. In our example, I'll be assigning the owner of the phone's line to the first button and configure buttons for the other three users below it. Finally, I'll add another button for the general line. The buttons are shown in Figure 30-4. Notice the system message (GAD Technology) shown on the bottom left of the screen. The lines need to be configured first. For each line, we need a configuration entry called an ephone-dn. The ephone-dn serves multiple purposes; first, it defines an extension on the system, and second, it provides a reference for us to use when configuring the phone buttons. Let's see how that works. Ephone-DN Since I'm the king boss, I get the first extension. To define it, I'll create the first ephone- R1-PBX(config)#ephone-dn 1 dual-line R1-PBX(config-ephone-dn)# The dual-line keyword enables this line to make or receive a call while already on a call. Generally, I make all lines dual-line capable. The next step is to define the line numb