Contractors working in telecommunications or data communications may find applications of voice over Internet protocol (VoIP) confusing. In addition, the proper use of unshielded twisted pair (UTP) cabling may pose some challenges. Furthermore, how the two items relate to one another also can create issues that electrical contractors must resolve.

VoIP is a phone service that operates using a high-speed Internet connection. It sends voice information in digital form in discrete packets over the Internet, versus the traditional circuit-switching protocols for voice traveling over the public switched telephone network (PSTN).

UTP is a form of wiring in which two conductors are wound together for the purpose of canceling out electromagnetic interference (EMI) from external sources and crosstalk between neighboring pairs. To be effective, the twist rates between the pairs must differ. It is the primary wire type for telephone usage and is very common for computer networking.

VoIP service can be handled on UTP cabling. It can be installed in both residential and commercial settings. One great difference between the residence and the commercial building is the amount of traffic on the VoIP lines. The residence, or SOHO (small office/home office), has fewer users than the commercial office building. The categories of UTP (Category 5e, 6, 6e and 6a) all can handle VoIP. The choice of category depends on the amount of traffic a home or company has and its future development plans.

VoIP can be divided into two types of services: phone-based and computer-based. These services enable you to make phone calls using either your regular phone, a VoIP phone or a computer headset with microphone. As opposed to a traditional landline, when you use VoIP to call a number, the call is sent over the Internet instead of over copper wires running out of your house. VoIP is considered IP telephony and is a more efficient, low-cost way of communicating with others.

Residential VoIP

In a residence, the shift from phone line-based voice communications to Internet-based will benefit your customer. The top benefit is saving money. VoIP service is cheaper and often is free through service providers such as Skype.

Another benefit is in structure. VoIP handles calls with packet switching, and data networks already understand that technology. By using it, telephone networks begin communicating like computers.

In addition, there also are many area codes from which to choose. For example, VoIP customers may choose their phone number from many area codes regardless of where they are calling from. You could choose a New York 212 area code and telephone number but use the phone in Seattle. The people you are calling in New York will be able to call you, as well, without incurring long distance charges.

Also, many VoIP providers offer free value-added features, such as caller ID or call forwarding.

The VoIP line can be a low-cost second line. When trying out the service, consumers may subscribe to it as a secondary phone line (for office or other uses). Once they have tested VoIP’s reliability, they may migrate their primary line to VoIP, too.

Lastly, calling home while traveling is easy because the analog telephone adapter—a device that allows one to use a traditional telephone with VoIP service—used with an analog phone enables users to place calls over any high-speed Internet connection. Though meant for home use only, because of its small size and portability, users can bring it wherever they want and can place or receive calls whenever they want. This can save on roaming fees.

UTP in the residence

Homeowners or other residential end-users may find definite advantages to cabling over Cat 3, Cat 5 or Cat 6 cable, other than just dollar savings, and its presence makes VoIP usage possible.

Using Cat 3 for VoIP may work for short distances and lower data rates. Cat 3 can handle up to 10 Mbps, but Cat 3 may not be effective in distributing the signal to other computers in a house. Some Internet providers deliver as much as 100 Mbps to the home.

Using Cat 5 or 5e for VoIP would work fine. The high-speed Internet “box” would connect to various computers in the home over Ethernet, and a handset would connect to the computer, which would be used to send/receive calls. That being said, a Cat 6 structured cabling system would work even better than Cat 5 or 5e.

The best solution to support VoIP and other networking is fiber. In the residence, it would deliver up to 100 Mbps now and may deliver 1 Gbps in the future. That signal is converted at the demarcation point or side of the house into an Ethernet signal running over the copper inside.

Commercial/business VoIP

It’s a big deal for a company to switch over to VoIP for its voice communications by riding on the company’s data network. Company concerns may include quality of service or performance and interoperability issues with the existing data networks. Putting voice on the data network creates security and interoperability concerns with serious service impacts.

Some advantages of using VoIP in a business include the following:

• With VoIP service, phone calls travel over the Internet as data, just as e-mail does.

• Today’s VoIP service has evolved and allows one to make and receive calls using standard phones or, even better, feature-rich IP phones.

• Sound quality has vastly improved.

• Packet switching allows one to make several calls in the same space it took to make only one call in a circuit-switched network.

• Data compression can further reduce the size of each call, saving the company more money.

If concerns about interoperability are an issue, another way to provide VoIP is to have a separate and more secure voice network that connects to the Internet protocol private branch exchange (IP-PBX). According to Frank Murawski of FTM Consulting Inc., even at higher levels of Category cabling, you need separate wiring for VoIP unless you are a small user. See the “VOIP Cabling Systems Market” report by FTM Consulting Inc. at

UTP in the commercial building

How does UTP fit into the commercial building environment? It’s important to consider types of cabling. Note that Cat 5e cabling will support VoIP Ethernet needs (10BASE-T, 100BASE-T or 1000BASE-T). Cat 6 cabling could be considered overkill for today, but with IP-based technology evolving as it is, one wouldn’t want to cable just for today unless expectations of staying in the current facility were short-term (less than 12 months). There are a couple of instances where Cat 6 makes sense: long-term occupancy, where the user considers it an upgradable path, and if the next step in VoIP is teleconferencing to the desktop with video. Beyond that, there is a Cat 6e cable, such as Mohawk’s GigaLAN Cat 6e cable, that provides proven support for gigabit Ethernet, IEEE 802.3af power over Ethernet for VoIP, and other Ethernet and broadband applications.

Fiber also may present itself against Cat 6a as soon as the cost of the optical-to-electrical converters is in line with the current copper cost base. In the end, project managers realize the economic impact of a VoIP installation and copper is still the most economical way to deliver 10GBASE-T to the desktop.

VoIP appears to be functionality that building or homeowners are seeking, and UTP is a way to achieve those capabilities. The electrical contractor should be well-versed in this terminology to answer the call.

Technical information about the residence supplied by John Pryma, Chair of TIA’s TR 42.2 Residential Cabling subcommittee. Technical information about commercial buildings provided by Mohawk, Leominster, Mass., (

MICHELSON, president of Jackson, Calif.-based Business Communication Services and publisher of the BCS Reports, is an expert in TIA/EIA performance standards. Contact her at or