NEC Projector LT20 User Manual

							27... English
Problem: The image is stretched when displaying 16:9 DVD.
The projector automatically detects 16:9 DVD and adjusts the aspect
ratio by digitizing to full screen with 4:3 default setting.
If the image is still stretched, you will also need to adjust the aspect
ratio by referring to the following:
Please select 4:3 aspect ratio type on your DVD player if you are
playing a 16:9 DVD.
If you can’t select 4:3 aspect ratio type on your DVD player, please
select 4:3 aspect ratio in the on-screen menu.
Problem: Lamp burns out or makes a popping sound
When the lamp reaches its end of life, it will burn out and may
make a loud popping sound.  If this happens, the projector will not
turn on until the lamp module has been replaced. To replace the
lamp, follow the procedures in the “Replacing the Lamp”. See
page 29.
Problem: LED lighting message
MessagePower LED StatusLamp
Orange Green LED LED
Standby State
  (Input power cord)
Lamp lightingFlashing
Power On
Power Off (Cooling)Flashing
Error (Lamp failed)Flashing Flashing
Error
Flashing Flashing
(Fan lock failed)
Error (Overheated)Flashing
Error
(Lamp no strike)
Problem: Message Reminders
“The lamp has reached the end of its usable life. Please replace the
lamp.” will be shown about 10 seconds, when lamp is nearing end
of life.
“Projector Overheated.” will be shown when the system tempera-
ture is too high.
“ The cooling fan has stopped.” will be shown when the fan is out
of order.
Appendices
Steady light =>
No light => 
						

							28English ...
Replacing the lamp
The projector will detect the lamp life itself.  It will show
you a warning message “The lamp has reached the end of its
usable life. Please replace the lamp.” When you see this
message, change the lamp as soon as possible.
Make sure the projector has been cooled down for at least
60 minutes before changing the lamp.
Warning: Lamp
compartment is hot!
Allow it to cool down
before changing lamp!
Lamp Changing Procedure:
1.Switch off the power to the projector by pressing the On/
Standby button.
2.Allow the projector to cool down at least 60 minutes.
3.Disconnect the power cord.
4.Use a screwdriver to remove the 2 screws from the cover.n
5.Push up and remove the cover.o
6.Remove the 2 screws from the lamp module.p
7.Pull out the lamp module. q
To replace the lamp module, reverse the previous steps.
Warning:To
reduce the risk of
personal injury, do not
drop the lamp module
or touch the lamp
bulb. The bulb may
shatter and cause
injury if it is dropped.
13
4
Appendices
2 
						

							29... English
Specifications
Light Valve - Single Chip DLPTM Technology by Texas Instruments
Number of Pixels- 1024 pixels(H) X 768 lines(V)
Displayable Color -16.7M colors
Projection Lens -F/2.7~2.88  f=28.43~32.75mm with 1.15x Manual
zoom lens
Projection Screen Size (Diag.) -31.7 to 246.1 inches (0.81 to 6.25 meters) Diagonal
Projection Distance -4.92 to 32.8 feet (1.5 to10.0 meters)
Video Compatibility -NTSC/NTSC 4.43/PAL/PAL-M/PAL-N/SECAM,
Component and HDTV compatible
- Composite video & S-Video capability
H. Frequency -15kHz~80kHz horizontal scan
V. Frequency -50Hz~85Hz vertical refresh
Power Supply -Universal AC input 100-240V ;
Input Frequency 50-60Hz
Power Consumption -200W
Input Current -2.3-1.0A (100-240V AC)
I/O Connectors - Power: AC power input socket
- Computer Input:
1x 15-pin D-Sub VGA for analog/component and
HDTV signal
- Video Input:
1x Composite video RCA input
1x S-Video input
Weight -2.2 lbs (1 kg)
Dimensions (W x H x D) -7.9 x 2.2 x 5.9 inches (200 x 56 x 150.5 mm)
Environmental -Operating Temperature: 41~95
oF (5~ 35oC)
Humidity: 80% maximum (Non-condensing)
- Storage Temperature: -4~140
oF (-20~60oC)
Humidity: 80% maximum (Non-condensing)
Safety Regulation -FCC, CE, VCCI, UL, cUL, TÜV-GS, S-TUV(Japan),
PSE(Japan), CB Report
Appendices 
						

							30English ...
VESA VGA64 0 x 35 07031 . 5
VESA VGA64 0 x 35 08537 . 9
VESA VGA64 0 x 40 08537 . 9
VESA VGA64 0 x 48 06031 . 5
VESA VGA64 0 x 48 07237 . 9
VESA VGA64 0 x 48 07537 . 5
VESA VGA64 0 x 48 08543 . 3
VESA VGA72 0 x 40 07031 . 5
VESA VGA72 0 x 40 08537 . 9
SVGA80 0 x 60 05635 . 2
SVGA80 0 x 60 06037 . 9
SVGA80 0 x 60 07248 . 1
SVGA80 0 x 60 07546 . 9
SVGA80 0 x 60 08553 . 7
VESA XGA1024 x 7686048 . 4
VESA XGA1024 x 7687056 . 5
VESA XGA1024 x 7687560 . 0
VESA XGA1024 x 7688568 . 7
* VESA SXGA115 2 x 86 47063 . 8
* VESA SXGA115 2 x 86 47567 . 5
* VESA SXGA115 2 x 86 48577 . 1
* VESA SXGA1280 x 9606060 . 0
* VESA SXGA1280 x 9607575 . 0
* VESA SXGA12 80  x 102 46063. 9 8
* VESA SXGA12 80  x 102 47579. 9 8
* VESA SXGA+14 00  x 105 06063. 9 8
M AC  16"83 2 x 62 474. 5 549.725
M AC  19"1024 x 7687560. 2 4
* MAC115 2 x 87 075. 0 668. 6 8
MAC G 464 0 x 48 06031. 3 5
i Mac DV1024 x 7687560 . 0
* i Mac DV115 2 x 87 07568. 4 9
* i Mac DV1280 x 9607575 . 0
Compatibility Modes
Remark :
1.> “
*”compressed
computer image.
2.> The interlaced
analog signals are not
supported.
Mode Resolution
Appendices
(ANALOG)
V.Frequency
(Hz)H.Frequency
(kHz) 
						

							A-1
Appendix
TravelCare Guide
TravelCare - a service for international travelers
This product is eligible for "TravelCare", NEC's unique international war-
ranty.
Please note that TravelCare coverage differs in part from coverage un-
der the warranty included with the product.
Services offered with TravelCare
This warranty allows customers to receive service on their product at
the NEC and NEC-designated service stations in the countries listed
herein when temporarily traveling internationally for business or plea-
sure.
For details on services offered by the different service stations, please
refer to the "List of TravelCare Outlets" below.
1 Repair services
The product will be repaired and delivered within 10 business days,
not including shipping time.
During the term of warranty, the cost of maintenance parts, labor
costs for repairs and shipping costs within the service station's cov-
erage area are covered by the warranty.
2 Replacement product rental service
If the customer desires, he or she can rent a replacement product
while the original product is being repaired.
Fee: US$200 for 12 days
This fee must be paid at the local service station in cash or credit
card.
The $200 rental fee is non-refundable even if the customer rents it
less than 12 days before returning.
The replacement product will be delivered within 3 business days.
If the customer did not return the replacement product within 12 days,
the customer will be charged the price of the unit.
If the customer returned the replacement product in a faulty or dam-
aged condition, the repair cost will be charged to the customer.
Note that this service is not offered in all countries and regions. Please
refer to the "List of TravelCare Outlets".
In addition, this replacement product rental service is not offered af-
ter the product's warranty has expired.
Term of warranty
1
a. Upon presentation of the warranty or receipt received upon pur-
chase:
Valid for the term indicated on the warranty or the normal term of
warranty for the country of purchase.
b. When only the product is brought in:
Valid for a period of within 14 months of the date of manufacture
indicated by the serial number attached to the product.
2 When a product whose term of warranty is expired is brought in:
Repairs will be offered for a fee. In this case the customer is not
eligible for the replacement product rental service.
3 In the following cases, repairs may be charged, even if the product's
warranty is still in effect:
1) If the term of warranty, model name, serial number and name of
the store of purchase are not indicated on the warranty or have
been altered.
2) Problems or damage caused by dropping or shocks during ship-
ment or movement by the customer or by improper handling by
the customers.
3) Problems or damage caused by improper usage or unwarrant-
able alterations or repairs by the customer.
4) Problems or damage caused by fire, salt damage, gas damage,
earthquakes, lightning damage, storm or flood damage or other
natural disasters or such external factors as dust, cigarette
smoke, abnormal voltage, etc.5) Problems or damage caused by use in hot or humid places, in
vehicles, boats or ships, etc.
6) Problems or damage caused by expendable supplies or devices
connected to the product other than those designated by NEC.
7) Problems caused by natural consumption, wear or deterioration
of parts under normal usage conditions.
8) Problems or damage to lamps and other expendable supplies,
included parts or optional parts.
9) Other conditions stipulated in the warranty included with the prod-
uct also apply.
NOTE:The product can be used overseas with voltages of 100 to 120V and 200
to 240V by using a power cable suited for the standards and power source volt-
age of the country in which the product is being used.
List of TravelCare Outlets
This list applies as of December 1, 2004.
For the most up-to-date information, please refer to the websites of the
service stations in the various countries on the List of TravelCare Out-
lets or to the NEC website at 
http://www.nec-pj.com.
In Europe
NEC Europe, Ltd. / European Technical Centre
Address: Unit G, Stafford Park 12, Telford TF3 3BJ, U.K.
Telephone: +44 1952 237000
Fax Line: +44 1952 237006
Email Address: [email protected]
WEB Address:
http://www.neceur.com
(Regions Covered)
EU: Austria*, Belgium*, Denmark*, Finland*, France*, Germany*,
Greece*, Ireland*, Italy*, Luxembourg*, The Netherlands*,
Portugal*, Spain*, Sweden* and the United Kingdom*
EEA: Norway*, Iceland and Liechtenstein
In North America
NEC Solutions (America), Inc.
Address: 1250 N. Arlington Heights Road, Suite 400,
Itasca, Illinois 60143, U.S.A.
Telephone: +1 800 836 0655
Fax Line: +1 800 356 2415
Email Address: vsd.tech-suppor [email protected]
WEB Address:
http://www.necvisualsystems.com
(Regions Covered)
U.S.A. *, Canada*
In Oceania
NEC Australia Pty., Ltd.
Address: New South Wales;
184 Milperra Road, Reversby 2212
Victoria;
480 Princess Hwy Noble Park 3174
South Australia;
84A Richmond Road, Keswick 5035
Queensland;
116 Ipswich Road, Woollongabba 4102
Western Australia;
45 Sarich Court Osborne Park 6017
Telephone: 131 632 (from domestic)
+61 8 8375 5706 (from overseas)
Fax Line: +61 8 8375 5757
Email Address: [email protected]
WEB Address:
http://www.nec.com.au
(Regions Covered)
Australia*, New Zealand 
						

							A-2
Appendix
Lenso Communication Co., Ltd.
Address: 292 Lenso House 4, 1st Floor, Srinakarin Road,
Huamark, Bangkapi, Bangkok 10240, Thailand
Telephone: +66 2 375 2425
Fax Line: +66 2 375 2434
Email Address: [email protected]
WEB Address:
http://www.lenso.com
(Regions Covered)
Thailand
ABBA Electronics L.L.C.
Address: Tariq Bin Ziyad Road, P.O.Box 327, Dubai,
United Arab Emirates
Telephone: +971 4 371800
Fax Line: +971 4 364283
Email Address: [email protected]
(Regions Covered)
United Arab Emirates
Samir Photographic Supplies
Address: P.O.Box 599, Jeddah 21421, Saudi Arabia
Telephone: +966 2 6828219
Fax Line: +966 2 6830820
Email Address: [email protected]
(Regions Covered)
Saudi Arabia
NOTE:In countries designated with an asterisk(*), replacement product rentalservice are offered.
In Asia and Middle East
NEC Viewtechnology,  Ltd.
Address: 686-1, Nishioi, Oi-Machi, Ashigarakami-Gun,
Kanagawa 258-0017, Japan
Telephone: +81 465 85 2369
Fax Line: +81 465 85 2393
Email Address: [email protected]
WEB Address:
http://www.nec-pj.com
(Regions Covered)
Japan*
NEC Hong Kong Ltd.
Address: 11th Floor, Tower B, New Mandarin Plaza, 14
Science Museum Road,
Tsim Sha Tsui East, Kowloon, Hong Kong
Telephone: +852 2369 0335
Fax Line: +852 2795 6618
Email Address: [email protected]
WEB Address:
http://www.nec.com.hk
(Regions Covered)
Hong Kong
NEC Taiwan  Ltd.
Address: 7F, No.167, SEC.2, Nan King East Road, Taipei,
Taiwan, R.O.C.
Telephone: +886 2 8500 1734
Fax Line: +886 2 8500 1420
Email Address: [email protected]
WEB Address:
http://www.nec.com.tw
(Regions Covered)
Taiwan
NEC Solutions Asia Pacific Pte. Ltd
Address: 401 Commonwealth Drive, #07-02, Haw Par
Technocentre, Singapore 149598
Telephone: +65 6 273 8333
Fax Line: +65 6 274 2226
Email Address: [email protected]
WEB Address:
http://www.nec.com.sg/ap
(Regions Covered)
Singapore
NEC Systems Integration Malaysia Sdn Bhd
Address:
Ground Floor, Menara TA One, 22, Jalan P. Ramlee,50250 Kuala Lumpur, Malaysia
Telephone: +6 03 2164 1199
Fax Line: +6 03 2160 3900
Email Address: [email protected]
WEB Address:
http://www.necmalaysia.com.my
(Regions Covered)
Malaysia
Tele Service Co., Ltd.
Address: 2nd Fl., Ire B/D. #2, 4Ga, Yangpyeng-Dong,
Youngdeungpo-Gu, Seoul, Korea 150-967
Telephone: +82 2 2163 4193
Fax Line: +82 2 2163 4196
Email Address: [email protected]
(Regions Covered)
South Korea 
						

							A-3
Appendix
TO: NEC or NEC's Authorized Service Station:
FM:
(Company & Name with signature)
Dear Sir (s),
I would like to apply your TravelCare Service Program based on attached registration and qualification sheet and agree with your
following conditions, and also the Service fee will be charged to my credit card account, if I don't return the Loan units within the
specified period. I also confirm following information is correct.     Regards.
Application Sheet for TravelCare Service Program
P-1/    ,
Country,
product purchased :
User's Company Name :
User's Company Address :
Phone No., Fax No. :
User's Name :
User's Address :
Phone No., Fax No. :
Local Contact office :
Local Contact office Address :
Phone No., Fax No. :
User's Model Name :
Date of Purchase :
Serial No. on cabinet :
Problem of units per User :
Required Service : (1) Repair and Return (2) Loan unit
Requested period of Loan unit :
Payment method : (1) Credit Card (2) Travelers Cheque (3) Cash
In Case of Credit Card :
Card No. w/Valid Date :
Date:      /       /       , 
						

							A-4
Appendix
Ve r.101/05 5. Loan Service Charges and Conditions:
Upon acceptance of this NEC Projector, Customer agrees to assume
liability for this loan unit.
The current cost of use of this loan unit is $200.00 USD for 12 calendar
days.
If Customer does not return the unit within the 12 calendar days, Cus-
tomer will be charged the next highest cost up to and including the full
list price to Credit Cards, which price will be informed by NEC Autho-
rized Service Stations. Please see the attached listing of contacts for
each country to arrange for pickup of the loan unit.
If you return to their country of origin with the loan unit, you will be
charged additional freight to return the unit to the loaning country.
Thank you for your understanding of this program.
Condition of your TravelCare Service Program
Enduser is requested to understand following condition of TravelCare
Service Program and complete the necessary information on the appli-
cation sheet.
1. Service Options:
There are 3 types of "Service" available. Enduser has to understand
following condition and is required to fill in the Application Sheet.
1) Repair and Return:
The 'Faulty unit' is sent or collected from the customer. It is repaired
and returned within 10 days to the customer, excluding transport time.
There may have a case, repair and return can't be done by NEC
Authorized Service Station, because of shortage of spare parts due
to same model is not sold in the territory.
2) Repair and Return with Loan: (This service is limited to some Ser-
vice Stations)
This service is offered to the Enduser, who cannot wait until their unit
is repaired.
The customer can borrow a unit for $200 up to 12 days. Customer
then sends in inoperable unit to nearest NEC Authorized Service
Station for service. In order to prevent collection problem, Enduser is
required to fill in Application Sheet.
Enduser needs to confirm the availability of the Service to NEC Au-
thorized Service Stations.
3) Loan Only:
For this service, NEC Authorized Service Station supplies the cus-
tomer with a loan unit for US$200 up to 12 days. Customer keeps the
inoperable unit and when customer returns home, customer arranges
to have the projector serviced in the home country.
2. Warranty  Exclusions:
This program does not apply if the Projector's serial number has been
defaced, modified or removed.
If, in the judgement of NEC Authorized Service Station or its agent the
defects or failures result from any cause other than fair wear and tear or
NEC neglect, or fault including the following without limitation:
1) Accidents, transportation, neglect, misuse, abuse, water, dust, smoke
or default of or by the Customer its employees or agents or any third
party;
2) Failure or fluctuation of electrical power, electrical circuitry, air condi-
tioning, humidity control or other environmental conditions such as
use it in smoking area;
3) Any fault in the attachments or associated products or components
(whether or not supplied by NEC or its agents which do not form part
of the Product covered by this warranty);
4) Any act of God, fire, flood, war, act of violence or any similar occur-
rence;
5) Any attempt by any person other than any person authorized by NEC
to adjust, modify, repair, install or service the product.
6) Any Cross-border charges such as, duty, insurance, tax etc.
3. Charges for Warranty Exclusions and Out of Warranty Case:
In case faulty unit is under warranty exclusions case or under Out of
Warranty period, NEC Authorized Service Station will Inform estimation
of actual service cost to the Enduser with reason.
4. Dead on Arrival (DOA):
Enduser must take this issue up with their original supplier in the coun-
try of purchase.
NEC Authorized Service Station will repair the DOA unit as a Warranty
repair, but will not exchange DOA unit with new units. 
						

							NEC SOLUTIONS’ PROJECTOR PRODUCTSNEC Solutions (America), Inc. (hereafter NEC Solutions) warrants
this product to be free from defects in material and workmanship
under the following terms.
HOW LONG IS THE WARRANTYNEC Solutions’ LT20 projector is covered by a two (2) year lim-
ited parts and labor warranty from the date of the first customer
purchase. The lamp when used under normal operating condi-
tions is warranted for 500 hours or 90 days, whichever comes
first.
WHO IS PROTECTEDThis warranty may be enforced only by the first purchaser, and is
not transferable.
WHAT IS COVERED AND WHAT IS NOT COVEREDExcept as specified below, this warranty covers all defects in
material or workmanship in this product.
NEC SOLUTIONS’ LIABILITY FOR ANY DEFECTIVE PRODUCT IS
LIMITED TO THE REPAIR OR REPLACEMENT OF THE PRODUCT
AT NEC SOLUTIONS’ OPTION. REPLACEMENT PRODUCTS MAY
BE NEW OR RECONDITIONED PRODUCTS, AND REPLACEMENT
PARTS MAY BE NEW OR SERVICEABLE USED PARTS. The follow-
ing are not covered by the limited warranty and NEC Solutions
shall not be liable for:
1. Any product which is not distributed in the U.S.A. or Canada
by NEC Solutions or which is not purchased, installed, and
operated in the U.S.A or Canada.
2. Any product on which the serial number has been defaced,
modified or removed.
3. Normal decrease in lamp light output over time.
4. Damage, deterioration or malfunction resulting from:
a. Accident, misuse, abuse, neglect, improper ventilation, fire,
dust, smoke, water, lightning or other acts of nature, unau-
thorized product modification, or failure to follow instruc-
tions supplied with the product.
b. Repair or attempted repair by anyone other than a NEC
Solutions authorized service center.
c. Any shipment of the product (claims must be presented to
the carrier).
d. Removal or installation of the product.
e. Any other cause which does not relate to a product defect.
f. Use of the product beyond normal operating conditions.
Normal operating conditions are defined as product use
not in excess of 8 hours per day and 260 days per year.
5. Cartons, carrying cases, shipping cases, batteries, external
cabinets, magnetic tapes, or any accessories used in connec-
tion with the product.
6. Service required as a result of third party components.
WHAT NEC SOLUTIONS WILL PAY FORNEC Solutions will pay labor and material expenses for covered
items, but NEC Solutions will not pay for the following:
1. Removal or installation charges.
2. Costs of technical adjustments, set-up, maintenance, or adjust-
ment of user controls.
3. Payment of shipping and related charges incurred in returning
the product for warranty repair.
LIMITED WARRANTY (USA and Canada only)
HOW YOU CAN GET WARRANTY SERVICE1. To obtain ser vice on your product, consult the dealer from whom
you purchased the product.
2.
Whenever warranty service is required, the original dated invoice
(or a copy) must be presented as proof of warranty coverage. In
order to obtain warranty service, you may be required to describe
and demonstrate the problem to your dealer or to NEC Solutions.
3. All products returned to NEC Solutions for service MUST have
prior approval. To receive approval or for the name of the
nearest NEC Solutions authorized service center, call NEC
Solutions at 800-836-0655.
4. It shall be your obligation and expense to ship the product,
freight prepaid, or to deliver it to a NEC Solutions authorized
service center, in either the original package or a similar pack-
age affording an equal degree of protection.
5.
In the event a product is returned to NEC Solutions for warranty
service, and it is determined that there is no product defect or that
the product condition is not covered by this limited warranty, a
diagnostic service fee may be charged to the customer.
LIMITATION OF IMPLIED WARRANTIESEXCEPT AS EXPRESSLY SET FORTH IN THIS LIMITED WARRANTY,
NEC SOLUTIONS MAKES NO OTHER WARRANTIES, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY IMPLIED
WARRANTIES OR CONDITIONS OF MERCHANTABILITY AND
FITNESS FOR A PARTICULAR PURPOSE. ANY IMPLIED WARRAN-
TIES THAT MAY BE IMPOSED BY LAW ARE LIMITED TO THE TERMS
AND DURATION OF THIS LIMITED WARRANTY.
EXCLUSION OF DAMAGESNEC SOLUTIONS’ LIABILITY FOR ANY DEFECTIVE PRODUCT IS
LIMITED TO THE REPAIR OR REPLACEMENT OF THE PRODUCT
AT NEC SOLUTIONS’ OPTION. NEC SOLUTIONS SHALL NOT
BE LIABLE FOR:
1. DAMAGE TO OTHER PROPERTY CAUSED BY ANY DEFECTS
IN THIS PRODUCT, DAMAGES BASED UPON INCONVE-
NIENCE, LOSS OF USE OF THE PRODUCT, LOSS OF TIME,
COMMERCIAL LOSS; OR
2. ANY OTHER DAMAGES, WHETHER INCIDENTAL, CONSE-
QUENTIAL OR OTHERWISE.
HOW STATE LAW RELATES TO THE WARRANTYSOME STATES DO NOT ALLOW LIMITATIONS ON HOW LONG
AN IMPLIED WARRANTY LASTS AND/OR DO NOT ALLOW THE
EXCLUSION OR LIMITATION OF INCIDENTAL OR CONSEQUEN-
TIAL DAMAGES, SO THE ABOVE LIMITATIONS AND EXCLU-
SIONS MAY NOT APPLY TO YOU. THIS LIMITED WARRANTY
GIVES YOU SPECIFIC LEGAL RIGHTS, AND YOU MAY HAVE
OTHER RIGHTS WHICH VARY FROM STATE TO STATE.
FOR MORE INFORMATION, CONTACT:
NEC SOLUTIONS (AMERICA), INC.
1250 N. Arlington Heights Road
Itasca, Illinois 60143-1248
TELEPHONE 800-836-0655
www.necvisualsystems.com
Customers are cautioned that product performance is affected by
system configuration, software, the application, customer data,
and operator control, among other factors. While NEC Solutions’
products are considered to be compatible with many systems, the
specific functional implementation by the customers of the prod-
uct may vary. Therefore, the suitability of a product for a specific
purpose or application must be determined by the customer and
is not warranted by NEC Solutions.
Printed in Taiwan 
						

							DECLARATION OF CONFORMITY
U.S. Responsible Party:
Address:
Tel. No.:NEC Solutions (America), Inc.
1250 N. Arlington Heights Road
Itasca, Illinois 60143
(630) 467-5000
Type of Product:
Equipment Classification:
Model:Projector
Class B Peripheral
LT20
We hereby declare that the equipment specified above
conforms to the technical standards as specified in the FCC Rules. 
This device complies with Part 15 of FCC Rules. Operation is subject to the following two conditions. 
(1) This device may not cause harmful interference, and (2) this device must accept any interference 
received, including interference that may cause undesired operation.