ENERGY STAR® Program Requirements
for Telephony
Eligibility Criteria (Version 2.0)
Below is the ENERGY STAR (Version 2.0) telephony product specification. A product must meet all of the
identified criteria if it is to be qualified as ENERGY STAR by its telephony manufacturer.
1) Definitions: Below is a brief description of telephony products and their common operational modes
as relevant to ENERGY STAR.
A.	Additional Handset: A commercially available electronic product with a handset, charging base
and battery, designed for use with Multi-Handset capable phone systems. To qualify, the charging
base of the cordless phone or its power supply must be designed to plug into a wall outlet and
there must not be a physical connection between the portable handset and the phone jack.
B.	Cordless Telephone: A commercially available electronic product with a base station and a
handset whose purpose is to convert sound into electrical impulses for transmission. Most of
these devices require an external power supply for power, are plugged into an ac power outlet for
24 hours a day, and do not have a power switch to turn them off. To qualify, the base station of
the cordless phone or its power supply must be designed to plug into a wall outlet and there must
not be a physical connection between the portable handset and the phone jack.
C.	Answering Machine: A commercially available electronic product—also known as a telephone
answering device (TAD)—whose purpose is to provide analog or digital storage of outgoing and
incoming telephone messages by connecting to the telephone line between the phone and the
phone jack. Most of these devices require an external power supply for power and are plugged
into an ac power outlet for 24 hours a day. To qualify, the answering machine or its power supply
must be designed to plug into a wall outlet.
D.	Combination Cordless Telephone/Answering Machine: A commercially available electronic
product in which the cordless telephone and answering machine are combined into a single unit
and which meets all of the following criteria: the answering machine is included in the base station
of the cordless telephone; it is not possible to measure the power requirements of the two
components separately without removal of the telephone casing; and the unit is connected to the
wall outlet through a single power cable. Most of these devices require an external power supply
for power, are plugged into an ac power outlet for 24 hours a day, and do not have a power switch
to turn them off. To qualify, the combination unit or its power supply must be designed to plug into
a wall outlet.
E.	Multi-Handset Model: This cordless phone system requires only one base and phone jack and, as
the name implies, can support multiple cordless handsets. Each handset added to the system
comes with a battery and a charging base.
F.	Cellular Telephone: A cellular telephone uses radio waves to connect to the cellular telephone
carrier. Cellular telephones are not eligible to carry the ENERGY STAR mark under this
specification as they are not considered cordless telephones.
G.	Corded Telephone: Corded telephones provide the same services as cordless telephones except
that there is a physical connection between the handset and the jack, which limits the user's
mobility while using the telephone. Corded telephones may or may not require an external power
supply for power. Corded telephones and combination units are not covered by this cordless
telephone specification and may not qualify as ENERGY STAR.
H.	Spread Spectrum Technology (SST): There are two types of spread spectrum technology, direct
sequence (e.g., digital spread spectrum or DSS) and frequency hoppers. Both types are available
in some digital telephony products to provide enhanced transmission range, extendable portable
ENERGY STAR Program Requirements for Telephony (Version 2.0)	3

numbers, and additional security.
I. Standby Mode: Lowest power consumption mode which cannot be switched off (influenced) by the
user and that may persist for an indefinite time when an appliance is connected to the main
electricity supply and used in accordance with the manufacturer's instructions. Note: The standby
mode is usually a non-operational mode when compared to the intended use of the appliance's
primary function.1 For the purposes of this specification, standby mode is the condition in which
the product is connected to a power source and is inactive (i.e., the unit is not transmitting a
conversation or recharging a low battery); in TAD the product is idle. In this mode, conventional
units may consume energy to operate circuitry and to overcharge rechargeable batteries.
J. Active Mode: The product is connected to a power source and is transmitting telephone
conversation, and/or playing/recording a message, and/or supplying current to a low battery to
charge it. The power requirement in this mode is typically greater than the power requirement in
Standby Mode.
K. Disconnect: The product is disconnected from all external power sources.
2)	Qualifying Products: Telephony product types that are covered by this EPA specification are: analog
and digital cordless telephones, multi-handset cordless telephones, answering machines, combination
cordless telephones/answering machines, multi-handset combination cordless telephones/answering
machines, and additional handsets using a variety of frequency ranges (e.g., 5.8 GHz, 2.4 GHz, 900
MHz, 46/49 MHz). Any cordless telephone, multi-handset cordless telephone, answering machine,
combination cordless telephone/answering machine, multi-handset combination cordless
telephones/answering machine, or additional handset that is marketed to the consumer in this way
and meets the applicable product definition in Section 1 is eligible to earn the ENERGY STAR. Please
note that mobile/cellular and corded telephones may not qualify for ENERGY STAR at this time.
3)	Energy-Efficiency Specifications for Qualifying Products: Only those products listed in Section 2
that meet the criteria below, may qualify as ENERGY STAR.
A. System-Level Efficiency Requirements
Table 1: Energy-Efficiency Criteria for ENERGY STAR Qualified Telephony
Product Category*
Version 1.0 Standby
Mode Requirements
Effective January 1,
2002 - October 31, 2006
Version 2.0 Requirements
Effective November 1, 2006

• Additional Handset
< 1.5 watts
< 1 watt
•	Answering Machine
•	Cordless Telephone
•	Multi-Handset Cordless Telephone
< 3.3 watts
< 2 watts
•	Answering Machine with SST
•	Cordless Telephone with SST
•	Multi-Handset Cordless Telephone with SST
<3.6 watts
< 2 watts
•	Combination Cordless
Telephone/Answering Machine
•	Multi-Handset Combination Cordless
Telephone/Answering Machine
< 4.0 watts
< 2.5 watts
•	Combination Cordless Telephone/
Answering Machine with SST
•	Multi-Handset Combination Cordless
Telephone/Answering Machine with SST
< 5.1 watts
< 2.5 watts
1 This definition is consistent with IEC 62301: Household Electrical Appliances - Measurement of Standby Power.
ENERGY STAR Program Requirements for Telephony (Version 2.0)	4

*Note: Any power consumed by the external power supply must be included when metering the unit for
ENERGY STAR qualification.
B. External Power Supply Efficiency Requirements: All telephony products designed for use with
external power supplies must use external power supplies that meet or exceed the ENERGY
STAR requirements for single voltage external ac-dc and ac-ac power supplies. Please note:
EPA is not requesting that telephony manufacturers test and submit data on external power
Once this Version 2.0 specification takes effect, telephony manufacturers who incorporate
external power supplies in their product design must use products that meet or exceed Tier 1 of
the ENERGY STAR specification for single voltage external ac-dc and ac-ac power supplies. (A
list of ENERGY STAR qualified power supplies is featured on the ENERGY STAR Web site, for
your reference.) If the external power supply specification is revised overtime (e.g., Tier 2 levels
are implemented), then similar modifications will be made to this Version 2.0 telephony
specification within a reasonable time period. For more information on the external power supply
program, visit the ENERGY STAR Web site at
4) Test Methodology: The following test procedure should be followed to ensure consistency in
measuring the system-level power requirements for electronics products. Outlined in Section A are the
ambient test conditions that should be respected when performing power measurements. These
conditions ensure that outside factors do not affect the test results and that the test results can be
reproduced. Sections B and C describe the specifications for testing equipment and the test method,
A. Test Conditions:
General Criteria:
Total Harmonic Distortion (Voltage):
< 3% THD
Ambient Temperature:
22°C ± 4°C
Terminations: External speaker terminals terminated per (IEC 107-1)
Supply Voltage:
North America/Taiwan:
115 volts ac, 60 Hz

230 volts ac, 50 Hz


100 Volts AC, 50 Hz or 60 Hz (either

frequency is acceptable)
B. Models Capable of Operating at Multiple Voltage/Frequency Combinations: Manufacturers shall
test their products based on the market(s) in which the models will be sold and promoted as
ENERGY STAR qualified. For products that are sold as ENERGY STAR in multiple international
markets and therefore rated at multiple input voltages, the manufacturer must test at and report
the required power consumption, energy performance, or efficiency values at all relevant
voltage/frequency combinations. For example, a manufacturer that is shipping the same model to
the United States and Europe must measure, meet the specification, and report test values at both
115 volts, 60 Hz and 230 volts, 50 Hz in order to qualify the model as ENERGY STAR in both
markets. If a model qualifies as ENERGY STAR at only one voltage/frequency combination (e.g.,
115 volts, 60 Hz), then it may only be qualified and promoted as ENERGY STAR in those regions
that support the tested voltage/frequency combination (e.g., North America and Taiwan).
ENERGY STAR Program Requirements for Telephony (Version 2.0)

C. Test Equipment: Manufacturers should measure and report the true standby power2 requirements
of the product. Doing so necessitates the use of a true power wattmeter. Because there are many
wattmeters from which to choose, manufacturers need to exercise care in selecting an appropriate
model. The following items should be considered when procuring equipment and performing the
1.	Ac Power Source (with sufficient output current for the test unit such that it meets the
requirement for ac line voltage, frequency stability, and THD).
2.	True Power Meter (with sufficient accuracy, resolution, crest factor rating, and bandwidth).
3.	Oscilloscope with Current Probe (to monitor ac line current waveform, amplitude, and
frequency. Optional but recommended).
4.	True RMS Voltmeter (to verify voltage at the input of test unit. Optional if ac source output is
sufficiently accurate).
5.	Frequency Counter (to verify frequency at the input of test unit. Optional if ac source output is
sufficiently accurate).
Crest Factor: Electronics equipment may draw current that is not sinusoidal.3 While virtually any
wattmeter can measure a standard current waveform, it is more difficult to select a wattmeter
when irregular current waveforms are involved.
It is critical that the wattmeter selected be capable of reading the current drawn by the product
without causing internal peak distortion (i.e., clipping off the top of the current wave). This requires
a review of the meter's crest factor rating and the current ranges available on the meter. Better
quality meters will have higher crest factor specifications and more choices of current ranges.
To determine the crest factor rating requirement of the meter and the proper current range
settings, the peak current (amperes (A) draw of the product under test in standby mode must first
be measured. This can be accomplished using an oscilloscope with a current probe.
A current range on the meter must be selected that is sufficient to register the peak current.
Specifically, the full-scale value of the selected current range multiplied by the crest factor of the
meter (for current) must be at least 15 percent greater than the peak current reading from the
oscilloscope to compensate for any measurement error. (Note: It is difficult to measure within 5
percent using an analog oscilloscope.) For example, if a wattmeter has a crest factor of 4 and the
current range is set on 3 A, the meter can register current spikes of up to 12 A. If measured peak
current is only 6 A, the meter would be satisfactory. If, however, the current range is set too high,
the meter may lose accuracy in measuring non-peak current. Therefore, some delicate balancing
is necessary. When choosing a meter, make sure that the crest factor is given for the current level
that you desire.
2	True power is defined as (voits)x(amperes)x(power factor) and is typically reported as watts. Apparent power is defined as
(volts)x(amperes) and is usually expressed in terms of VA or volt-amperes. The power factor for equipment with switching power
supplies is always less than 1.0; therefore, true power is always less than apparent power.
3	The crest factor of a current waveform is defined as the ratio of the peak current (amperes) to the rms current (amperes). The crest
factor for a sinusoidal 60 Hz current waveform is always 1.4. The crest factor for a current waveform associated with a product
containing a switching power supply will always be greater than 1.4 (though typically no higher than 8).
ENERGY STAR Program Requirements for Telephony (Version 2.0)	6

Figure 1
Sinewave Current
Frequency Response: Another issue to consider when selecting a wattmeter is the frequency
response rating of the meter. Electronics equipment may cause harmonic waveforms that can
lead to inaccuracies in the power measurements. For example, electronics equipment powered by
switching power supplies typically produces odd harmonics up to the 21st. To ensure that the
harmonics are properly addressed, ENERGY STAR recommends the use of a wattmeter with
frequency response of at least 3 kHz. This will account for harmonics up to the 50th, which is
recommended by IEC 555.
Resolution: Manufacturers should choose a wattmeter that can provide resolution of 0.1 watt or
Accuracy: Catalogues and specification sheets for wattmeters typically provide information on the
accuracy of power readings that can be achieved at different range settings. If the power
measurement is very close to the energy-efficiency guideline specified in these Program
Requirements (Eligibility Criteria), a test procedure with greater accuracy will be necessary. For
example, if the ENERGY STAR specification is 1.0 watt or less and the resulting accuracy of the
wattmeter at the test settings is ± 0.1 watts, then a power measurement of less than 0.9 watts will
ensure that the product qualifies for ENERGY STAR.
Calibration: To maintain their accuracy, wattmeters should be calibrated every year with a
standard that is traceable to the US National Bureau of Standards (NBS).
D. Test Method: The following are the steps to be used to measure the true power requirements of
the product under test (PUT) in standby mode. To view the definition of true power, refer to
Footnote 2 on page 6.
1.	Power the PUT. When rechargeable batteries are involved, the PUT must be fully charged
(allow up to 24 hours).
2.	Power on all test equipment and properly adjust operation range. Connect the test equipment
and PUT.
3.	Check that the PUT is connected to an external phone jack before and during testing. This is
done to ensure that the product is tested in a manner consistent with the way the consumer will
use it.
ENERGY STAR Program Requirements for Telephony (Version 2.0)	7

4.	Check that the PUT has all settings equal to the factory default settings (i.e., unit must be in the
condition shipped to the customer).
5.	Verify that the PUT is in standby mode (not disconnect mode).
6.	Either verify that the wall outlet power is within specifications or adjust the ac power source
output as described in Section A (e.g., 115 Vrms ± 3 Vrms, 60 Hz ± 3 Hz).
7.	Set the power meter current range. The selected full scale value multiplied by the crest factor
rating (Ipeak/lrms) of the meter must be greater than the peak current reading from the
8.	After the PUT reaches operating temperature and the readings on the power meter stabilize,
(times may vary depending on product) take the true power reading in watts from the power
9.	Record the test conditions and test data. The measurement time shall be sufficiently long to
measure the correct average value to within a +10% - 0% error, up to 24 hours but no less than
2 hours. If the device has different standby modes that can be manually selected, the
measurement should be taken with the device in the most power consumptive mode. If the
modes are cycled through automatically, the measurement time should be long enough to
obtain a true average that includes all modes.
5)	Effective Date: The date that manufacturers may begin to qualify products as ENERGY STAR, under
the Version 2.0 specification, will be defined as the effective date of the agreement. The ENERGY
STAR telephony (Version 2.0) specification shall go into effect on November 1, 2006.
A. Qualifying and Labeling Products Under the Version 2.0 Specification: All products, including
models originally qualified under Version 1.0, with a date of manufacture on or after November
1, 2006 must meet the Version 2.0 requirements in order to bear the ENERGY STAR mark. The
date of manufacture is specific to each unit and is the date (e.g., month and year) on which a
unit is considered to be completely assembled.
6)	Future Specification Revisions: EPA reserves the right to change the specification should
technological and/or market changes affect its usefulness to consumers or industry or its impact on
the environment. In keeping with current policy, revisions to the specification will be discussed with
ENERGY STAR Program Requirements for Telephony (Version 2.0)