Voice over Internet Protocol (VoIP) Phones


VoIP phones, which became eligible for the ENERGY STAR label in 2014, sit atop more and more office desks in America. They can be a significant energy user in the office.  In fact, an older VoIP phone could use up to 10 watts of power 24 hours per day – using as much energy as that nearby desktop computer which is typically on only during working hours![1]   ENERGY STAR certified VoIP phones:

  • Use approximately 40 percent less energy than conventional VoIP phones.
  • Come with advanced features that allow the phone to power down and enter an “off” mode at designated times or during periods of inactivity – via either user or network control. 

VoIP phones convert sound into Internet Protocol data packets for transmission through an Ethernet connection. Conventional analog telephones convert sound into electrical analog waveforms for transmission through the Public Switched Telephone Network (PTSN). According to IBISWorld's VoIP in the U.S. report, the VoIP phone market has increased 16.7 percent annually over the last five years.

In about a decade, using VoIP to make phone calls has gone from a hobby to being a widely used platform that is in the process of replacing standard analog telephone service. It has become so pervasive that people no longer realize they are using VoIP when they make a call.

[1] Assume desktop computer using around 40 watts (average between ES and non-ES desktop based on data from V.6 computer spec analysis) and on 40 hours a week with sleep settings activated or shutoff at night (1600 watt-hours per week) versus an old VoIP phone using 10 watts for 168 hours power week (1680 watt-hours per week).   

VOIP Phone image

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Buying Guidance [1]

ENERGY STAR certified VoIP phones use less energy and can power down at night to save you money.  In fact, a 100-person organization upgrading to ENERGY STAR certified VoIP phones can save $700 to $1,200 in electricity over the phones’ lifetime.  A 2,000-person organization can save $14,000 to $24,000.

What is VoIP?

VoIP converts speech to a digital signal. The process generally compresses the speech data, encodes it, breaks it into data packets, and sends these data packets over the internet like normal internet traffic. Encoding is done using one of a number of speech CODECs[2].  At the call destination the packets are reassembled, decoded using the appropriate CODEC, and converted to analog audio that can be heard by the call receiver.
Call quality is affected by the volume of internet traffic sharing the call’s bandwidth. In some cases, the quality of the calls may drop if available bandwidth is limited, which could lead to delays, calls cutting out, and inaudible conversations. While many see this as a big drawback to VoIP, a stable broadband connection seldom produces poor call quality.

Types of VoIP Phones

There are three ways to make a call using VOIP: using a VoIP phone, using a VoIP adapter, or using a computer with speakers and a microphone. As shown in Table 1 below, there are a variety of ENERGY STAR certified VoIP phones to choose from, each with different features and functionality. 

Table 1: Types of VoIP Phones Covered by ENERGY STAR

Phone Type Description
Hardware or Desktop Corded Telephone Hardware VoIP phones look like conventional phones, with a permanent physical connection between handset and the network, but feature integrated VoIP software. They connect to the broadband network using their own Ethernet connection and do not need a computer to function.
Wireless Consisting of a handset, cradle, and battery, wireless VoIP phones have built-in Wi-Fi or DECT[3] transceivers that allow units to connect to the wireless network in a home or office. Wireless VoIP phones may have a longer range than traditional cordless phones, but is more limited than mobile/cellular phones as it relies on nearby wireless routers or access points to make calls.
Conference VoIP telephone without a handset that utilizes a speakerphone for all communications and is primarily used for conference calls.

Softphones, USB VoIP, Video phones, and analog phones with a VoIP are not currently covered by the ENERGY STAR specification.

VoIP Phone Features

VoIP phones have a wide variety of features.  For example, a wireless phone allows the user more freedom of movement and can be used outside of the home by simply connecting to a Wi-Fi network.  All VoIP hardware phones should have the following basic features in order to work:

  • Capable of supporting the IP protocol that comes with the protocol suite.
  • At least one RJ-45 port for local area network (LAN) connection; and
  • A keypad for dialing.

 As shown in Table 2, there are many additional VoIP phone features available.

Table 3: Additional Features
Feature Description
LCD Display Screen An LCD screen allows users to access features like caller identity. More advanced phones feature color displays to access information, such as graphical directories.
Multiple Programmable Feature Keys Multiple programmable feature keys give users an interface to deal with basic and advanced phone features without necessarily needing a computer connection.
Ports for Network and/or Computer Connections An RJ -11 port allows the phone to be connected to an ADSL[4] line and an RJ -45 port allows LAN connection. Where there are multiple RJ-45 ports the phone can be used as a switch that can connect other network devices or phones to the network.
Multiple Language Support Multiple language support allows users who are more comfortable in a language other than English to access their phones and phone features in their native languages.
Built-In Headset Jack A built-in headset jack allows one to attach a headset to the phone for hands-free use.
Personalized Ringing Tones The ability to set personalized ringtones allows the user to identify the caller purely from the telephone ringtone.
Data Encryption Data encryption reduces threats to data security on the network.

Questions To Ask Yourself Before Purchasing VOIP Phones

  • What phone system or service provider are you currently using? What good is a VoIP Phone if it is not compatible with the phone system or service provider that you are using? With the advent of open source phone systems, SIP[5], and BYOD[6] service providers, it’s easy to think that every VoIP Phone works with every phone system or service. Unfortunately this is not the case so make sure you know what protocols and CODECs are supported by your VoIP Phone system and VoIP provider before buying. For example, although most VoIP Phones support SIP and the major voice CODECs, sometimes your provider might only support a H.323, MGCP, or SCCP compatible VoIP Phone or a VoIP Phone that supports the GSM codec.
  • Who will be using these VoIP Phones? Depending on the job function (or position) of the person using the VoIP Phone, there will be a different set of needs and each person will be looking for something different in a VoIP Phone.
  • What features and functionality does that person/position need? Most people want standard features such as Call Waiting, Call Transfer, Call Parking, Conference, etc. What you need to look for are needs such as a speakerphone, a large display and sidecar capability for extra extensions.
  • How many incoming calls will the person/position receive at a time? This is an important question because it will determine how many lines a VoIP Phone should have. While the average office worker will probably be okay with three to five line appearances, operators, administrators and receptionists will typically need more lines.
  • Do you need a VoIP Phone with a data switch port? In many offices there is only one Ethernet connection run per workstation. If this is true for you then both the desktop computer and the VoIP Phone will need to share a single Ethernet connection. In this situation you will need a VoIP Phone with dual RJ45 Ethernet ports. If your office already has a Voice LAN (separate voice network) set-up then you should have an Ethernet drop run to the desktop just for the VoIP Phone. This will allow you to use a VoIP Phone that has a single RJ45 Ethernet port (and save on the cost of the VoIP Phone).
  • Will you be utilizing Power over Ethernet with this deployment? If you are currently (or plan on) using Power over Ethernet you will need a VoIP Phone that supports Power over Ethernet. If you are not using Power over Ethernet and simply using AC power make sure you have an extra outlet at each work station to power the VoIP Phone.

Be sure to look for the ENERGY STAR when shopping for a VoIP phone

Current Specification Effective Date:  October 1, 2014

VoIP Phones Key Product Criteria: ENERGY STAR

Learn How a Product Earns the Label

[1] This guidance was taken from the following websites:

[2] A CODEC is a device or computer program capable of encoding or decoding a digital data stream or signal -- "coder-decoder".

[3] Digital Enhanced Cordless Telecommunications, a cordless communication standard.

[4] Asymmetric digital subscriber line (ADSL) is a type of digital subscriber line (DSL) technology, a data communications technology that enables faster data transmission over copper telephone lines than a conventional voiceband modem can provide.

[5] SIP: Session Initiation Protocol is the de facto standard protocol for establishing, conducting and ending a VoIP call.

[6] Bring Your Own Device

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