How To Install Voice Over IP

Especially for green-field sites and existing offices that are undergoing massive IT overhauls, VoIP offers single-wire simplicity and a one-stop management solution for all voice and data traffic. This recipe describes a green-field implementation of a small-office VoIP network. You'll need 10 ingredients; I will refer to Cisco gear, though you can use equivalent products from other vendors, such as Nortel or Siemens.

Here's what to get: a Cisco 3745 router; Cisco DSP network module; Cisco IOS IP Plus Software 12.2.15ZJ; Cisco CallManager Express (CCME) voice-handling software; Cisco Unity Express network module; Cisco 7912G VoIP phones; Cisco phone, model 7940G or higher; T1/FXO network module; Line Powered Ethernet Switching, model NM-16ESW-PWR; and Cat-5 cabling.

Let's start building the VoIP network.

1. Before any internal work is done, arrange an outside connection with the customer's telecom-services provider. Find out the type of connection and order the suitable network module.

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2. Assemble the VoIP gear. All of the aforementioned parts may be purchased preinstalled from Cisco. Our contacts at Cisco dubbed this configuration the CISCO3745-V-CCME-A bundle.

3. Connect the FXO/T-1 network module to the central office trunk.

4. Using your Cat-5 cabling, deploy the IP phones. Remember that each phone has a two-port switch, so most workspaces will only need a single line run from router or workgroup switch to the desktop. Link each phone with the router, then connect the desktops to the phone's other 10/100Base-T port.

5. Turn on the central timekeeper. Cisco ships routers with the Network Time Protocol service disabled, but it should be turned on for smooth operation and easier configuration of new phones.

6. CCME can automatically discover and configure your phones ("On the Hook," center). Launch telephony-service setup from an IOS command-line interface (CLI) prompt.

7. Configure a basic, fully consultative transfer system. Both blind (immediate connection) and consultative transfers are supported.

8. Save clients money by excluding all 1-900 number calls using this simple CLI sequence: telephony-service/after-hours block pattern 16 .1900 7-24.

9. Set the CLI aside. CCME relies heavily on a Web-based GUI configuration. If the router was purchased new, its HTTP server is disabled by default. Coordinate with the systems administrator to enable HTTP access for admin accounts.

10. Use the CCME GUI to create any additional administrator accounts and to set up user accounts for each phone so employees are authorized to configure voicemail and perform other basic tasks.

11. In the CCME GUI, verify that users have their desired extensions. The phones were auto-discovered and numbered sequentially with the setup wizard, but some clients may require vanity extensions for certain users.

At this point, the CCME GUI is loaded with complex features, and even more esoteric configurations are possible.

On the Hook
Before running the Wizard to configure your client's phones, be prepared to answer the following questions: