Connecting the Cisco IP phone 7940G

The inbuilt Cisco two-port Ethernet switch allows for a direct connection of the IP phone to a 10/100BASE-T Ethernet network via an RJ-45 interface. A single LAN connection will be enough for both the phone and a nearby PC.

The system administrator can designate separate virtual LANs (VLANs) for the PC and Cisco IP Phones providing improved security and reliability of voice and data traffic.

The Cisco IP Phone 7940G can also receive power down the LAN from any of the Cisco inline power-capable blades and boxes

Network Requirements
.The network must have a working VOIP network, which means Voice over IP (VoIP) configured on your Cisco routers and gateways
. Cisco CallManager* Release 3.0 or higher installed in your network and configured to handle call processing
. IP network that supports DHCP or manual assignment of IP address, gateway, and subnet mask

Adding a Cisco IP Phone Using Cisco CallManager
The IP phone has to be added to the CallManager before we can actually use it. This is done with Cisco CallManager Administration using either auto-registration or without auto-registration.

Auto-registration allows you to automatically add Cisco IP Phones to Cisco CallManager Administration simply by plugging them into a Cisco CallManager network. Auto-registration automatically assigns a directory number (selected from a range of numbers) to the telephone.

By default, auto-registration is turned off. When Cisco CallManager Administration is configured, you can turn on auto-registration by specifying a range of numbers from which auto-registration can choose directory numbers. Then, when new phones are added, they are automatically assigned the next available directory number. If a phone is moved to a new location, its phone number does not change.

Turning on Auto-Registration:
.Open Cisco CallManager Administration.
.Click Configuration.
.In the Auto-Registration area, click Configure. Type the start and end directory numbers (provided by the telephone company).
.Click Update. (The range of directory numbers auto-registration can use is configured, and auto-registration is enabled. When a new phone is added to the system, its directory number is automatically assigned by auto-registration).

Turning auto-registration off prevents unauthorized devices from registering with and gaining access to the Cisco CallManager.

Turning off Auto-Registration:
.Open Cisco CallManager Administration.
.Click Configuration.
. In the Auto-Registration area, click Configure. ( Type the same directory number in both the start number and end number boxes. For example, type 1000 as the start number, and 1000 as the end number).
.Click Update.( Auto-registration is turned off. New phones added to the system must be manually configured in Cisco CallManager Administration).


*Cisco CallManager: A software that runs on a Windows 2000 server and sets up and tears down calls between phones, integrating traditional PBX functionality with IP network. Cisco CallManager manages the components of the IP telephony system—the phones, access gateways, and the resources necessary for such features as call conferencing and route planning.

(More on CallManager some other time…)