Eye Safety NOT an Issue with Plaintree System's LED Optical Wireless Links

Apr 18, 2001, 01:00 ET from Plaintree Systems Inc.

    OTTAWA, April 18 /PRNewswire/ - Plaintree Systems Inc. (OTC BB: LANPF,
 TSE: LAN) - Recent claims of product eye-safety being made by certain laser
 optical wireless communications companies "can lead unwary purchasers into a
 false sense of security regarding health issues and leave them exposed to
 possible litigation," said David Watson, President and Chief Executive Officer
 of Plaintree Systems Inc.
     Optical wireless (OW) is viewed as an easily deployable technology and a
 cost-effective means of solving the problem of the broadband access
 bottleneck. OW systems employ either laser or LED transmitters and both
 operate in the infrared region of the electromagnetic spectrum. However, they
 differ in some key aspects, particularly with respect to eye-safety,
 reliability, and atmospheric propagation.
     "We are seeing more and more articles and reports on Free Space Optics
 (FSO) and optical wireless systems where eye-safety is always brought up as an
 issue. It is important that all potential users understand the inherent
 differences between lasers and Light Emitting Diodes (LEDs). In particular,
 Plaintree believes that it is essential that all potential operators
 appreciate the difference between a Class 1 and a Class 1M eye hazard rating,"
 Mr. Watson continued.
     "Plaintree's LED optical wireless OW links conform with a Class 1 rating,
 the most eye-safe according to the standards set by the International
 Electrotechnical Commission (IEC) and the American National Standards
 Institute (ANSI)," continued Watson.
     Plaintree is currently selling the WaveBridge 500 series of OW links that
 have transmission capacities up to 12 Mbps (megabits per second). Its next
 release, currently completing development, is the WaveBridge 700 series which
 will provide capacities up to 155 Mbps.
     "In almost all conversations we have had with our current and potential
 customers, their first issue on the table is eye safety. Some of our
 competitors are claiming their products are eye-safe because they have a Class
 1M rating," Watson continued, "but the recent update to the IEC eye safety
 standard (IEC60825 Amendment 2) that introduced the new Class 1M rating makes
 it clear that invisible laser beams transmitted from Class 1M systems are
 dangerous to view directly when using optical aids such as binoculars that can
 increase the power entering the eye by 50 times or more."
     The use of binoculars or gunsights is common as they are required in the
 alignment procedures of some optical wireless equipment. Furthermore, the path
 of the optical beam is not fully under the control of the operator who has no
 means of preventing inadvertent viewing by the public or maintenance staff and
 the possibility of resulting eye damage.
     David Kahn, Vice President of Product Development, at Plaintree agrees.
 "Plaintree's LED-based products are rated IEC Class 1, and that means eye-safe
 with or without binoculars under all foreseeable viewing conditions. Unlike
 microwaves and radio-frequency waves, optical waves do not generally penetrate
 and dissipate within interior body tissue. An important exception occurs in
 the case of the eyes. The pupil of the eye provides a window into the interior
 of the eye, and optical power passing through the pupil will generally end up
 being absorbed, usually on the retina at the back of the eye. The retina is a
 very sensitive area and can be damaged by strong light and that includes
 invisible infrared light."
     Mr. Kahn, who also teaches Optical Communication Systems at the
 University of Ottawa, has degrees from the University of Wales and the
 University of Southampton where he specialized in quantum and optoelectronics.
     Mr. Kahn explained further. "Laser light is far more dangerous to the
 eyes than LED light of the same power. This is because the eye is able to
 accommodate and concentrate laser light to a very small retinal spot several
 wavelengths in diameter resulting in a high power density. In contrast, LED
 light, being from an extended source, cannot be efficiently focussed down to
 much less than the source area, typically half a millimetre in diameter.
 Consequently, the potential retinal power density from a LED is over a
 thousand times less than that from a laser of the same power.
     Moreover, when LED light is concentrated using binoculars, the apparent
 source area increases further, preventing a corresponding increase in retinal
 power density. The standards indicate that the maximum safe power level,
 called the Accessible Emission Limit (AEL) entering the eye from a point
 source such as a laser at a typical infrared wavelength is around three
 quarters of a milliwatt, whereas the AEL from an extended source such as a LED
 transmitter can be up to ten times greater."
     There are three prime safety standards for the rating of products with
 laser or LED emissions. The IEC 60825-1 Edition 1 (1993) (Safety of Laser
 Products Part 1. Equipment classification, requirements and user's guide) with
 its two subsequent amendments addresses both devices. ANSI Z136.1 (1999) (Safe
 Use of Lasers) considers only lasers, while ANSI RP-27 (1996) (Recommended
 Practice for Photobiological Safety for Lamp Systems) covers non-laser
 sources.
     The IEC laser safety standard defines various classes or hazard levels
 associated with products and specifies what steps must be taken to identify
 them and protect users and the public. Class 1 devices are considered eye-safe
 under any foreseeable conditions. Class 1M devices are dangerous to view when
 using binoculars and require a warning notice or label. All the other classes
 are hazardous to the naked eye and require further protective measures.
     Plaintree's WaveBridge series of OW links for Internet Service Providers,
 cellular operators and campus networks, provide high-speed connections,
 bypassing planning delays and the need for expensive cable installation and
 frequency licensing.
     The problem, as Mr. Watson sees it, is that there isn't enough
 differentiation made between LED and laser systems, particularly with respect
 to eye-safety. "We like to use the analogy of the television remote control
 which is a LED-based product and the laser pointer to compare the two," stated
 Mr. Watson. "Which one would you rather look at?"
 
     About Plaintree Systems
     -----------------------
     Founded in 1988, Plaintree Systems Inc. is a manufacturer of optical
 wireless links, network switches, and LAN and telecommunications products.
 Using infrared LED technology, Plaintree's high-quality products offer high-
 speed data and voice transmission without any licensing requirements. These
 links are easy to install. Once installed the links are safe, secure,
 reliable, and robust. Unlike other network solutions, they can be densely co-
 located to provide high bandwidth connectivity without spectrum congestion
 problems associated with the crowded airwaves. The technology is a cost-
 efficient alternative to the expense of laying cable over the 'last mile'.
 Internet service providers and cellular operators are some of the potential
 markets for Plaintree's systems. Another high-potential market is at airports,
 where radio emissions abound and are tightly restricted.
     Plaintree Systems Inc. is headquartered in the Ottawa region and operates
 manufacturing facilities for switches and wireless products in Arnprior,
 Ontario. Plaintree is publicly traded in Canada on the Toronto Stock Exchange
 and in the U.S. on the Nasdaq Bulletin Board, with 86,059,869 shares
 outstanding. Plaintree maintains a worldwide web site at
 http://www.plaintree.com.
 
     This press release may include statements that are forward-looking and
 based on current expectations. The actual results of the company may differ
 materially from current expectations. The business of the company is subject
 to many risks and uncertainties, including changes in markets for the
 company's products, delays in product development and introduction to
 manufacturing and intense competition. For a more detailed discussion of the
 risks and uncertainties related to the company's business, please refer to
 documents filed by the company with the U.S. Securities and Exchange
 Commission and Canadian regulatory authorities, including the company's
 prospectus dated July 10, 2000.
 
 

SOURCE Plaintree Systems Inc.
    OTTAWA, April 18 /PRNewswire/ - Plaintree Systems Inc. (OTC BB: LANPF,
 TSE: LAN) - Recent claims of product eye-safety being made by certain laser
 optical wireless communications companies "can lead unwary purchasers into a
 false sense of security regarding health issues and leave them exposed to
 possible litigation," said David Watson, President and Chief Executive Officer
 of Plaintree Systems Inc.
     Optical wireless (OW) is viewed as an easily deployable technology and a
 cost-effective means of solving the problem of the broadband access
 bottleneck. OW systems employ either laser or LED transmitters and both
 operate in the infrared region of the electromagnetic spectrum. However, they
 differ in some key aspects, particularly with respect to eye-safety,
 reliability, and atmospheric propagation.
     "We are seeing more and more articles and reports on Free Space Optics
 (FSO) and optical wireless systems where eye-safety is always brought up as an
 issue. It is important that all potential users understand the inherent
 differences between lasers and Light Emitting Diodes (LEDs). In particular,
 Plaintree believes that it is essential that all potential operators
 appreciate the difference between a Class 1 and a Class 1M eye hazard rating,"
 Mr. Watson continued.
     "Plaintree's LED optical wireless OW links conform with a Class 1 rating,
 the most eye-safe according to the standards set by the International
 Electrotechnical Commission (IEC) and the American National Standards
 Institute (ANSI)," continued Watson.
     Plaintree is currently selling the WaveBridge 500 series of OW links that
 have transmission capacities up to 12 Mbps (megabits per second). Its next
 release, currently completing development, is the WaveBridge 700 series which
 will provide capacities up to 155 Mbps.
     "In almost all conversations we have had with our current and potential
 customers, their first issue on the table is eye safety. Some of our
 competitors are claiming their products are eye-safe because they have a Class
 1M rating," Watson continued, "but the recent update to the IEC eye safety
 standard (IEC60825 Amendment 2) that introduced the new Class 1M rating makes
 it clear that invisible laser beams transmitted from Class 1M systems are
 dangerous to view directly when using optical aids such as binoculars that can
 increase the power entering the eye by 50 times or more."
     The use of binoculars or gunsights is common as they are required in the
 alignment procedures of some optical wireless equipment. Furthermore, the path
 of the optical beam is not fully under the control of the operator who has no
 means of preventing inadvertent viewing by the public or maintenance staff and
 the possibility of resulting eye damage.
     David Kahn, Vice President of Product Development, at Plaintree agrees.
 "Plaintree's LED-based products are rated IEC Class 1, and that means eye-safe
 with or without binoculars under all foreseeable viewing conditions. Unlike
 microwaves and radio-frequency waves, optical waves do not generally penetrate
 and dissipate within interior body tissue. An important exception occurs in
 the case of the eyes. The pupil of the eye provides a window into the interior
 of the eye, and optical power passing through the pupil will generally end up
 being absorbed, usually on the retina at the back of the eye. The retina is a
 very sensitive area and can be damaged by strong light and that includes
 invisible infrared light."
     Mr. Kahn, who also teaches Optical Communication Systems at the
 University of Ottawa, has degrees from the University of Wales and the
 University of Southampton where he specialized in quantum and optoelectronics.
     Mr. Kahn explained further. "Laser light is far more dangerous to the
 eyes than LED light of the same power. This is because the eye is able to
 accommodate and concentrate laser light to a very small retinal spot several
 wavelengths in diameter resulting in a high power density. In contrast, LED
 light, being from an extended source, cannot be efficiently focussed down to
 much less than the source area, typically half a millimetre in diameter.
 Consequently, the potential retinal power density from a LED is over a
 thousand times less than that from a laser of the same power.
     Moreover, when LED light is concentrated using binoculars, the apparent
 source area increases further, preventing a corresponding increase in retinal
 power density. The standards indicate that the maximum safe power level,
 called the Accessible Emission Limit (AEL) entering the eye from a point
 source such as a laser at a typical infrared wavelength is around three
 quarters of a milliwatt, whereas the AEL from an extended source such as a LED
 transmitter can be up to ten times greater."
     There are three prime safety standards for the rating of products with
 laser or LED emissions. The IEC 60825-1 Edition 1 (1993) (Safety of Laser
 Products Part 1. Equipment classification, requirements and user's guide) with
 its two subsequent amendments addresses both devices. ANSI Z136.1 (1999) (Safe
 Use of Lasers) considers only lasers, while ANSI RP-27 (1996) (Recommended
 Practice for Photobiological Safety for Lamp Systems) covers non-laser
 sources.
     The IEC laser safety standard defines various classes or hazard levels
 associated with products and specifies what steps must be taken to identify
 them and protect users and the public. Class 1 devices are considered eye-safe
 under any foreseeable conditions. Class 1M devices are dangerous to view when
 using binoculars and require a warning notice or label. All the other classes
 are hazardous to the naked eye and require further protective measures.
     Plaintree's WaveBridge series of OW links for Internet Service Providers,
 cellular operators and campus networks, provide high-speed connections,
 bypassing planning delays and the need for expensive cable installation and
 frequency licensing.
     The problem, as Mr. Watson sees it, is that there isn't enough
 differentiation made between LED and laser systems, particularly with respect
 to eye-safety. "We like to use the analogy of the television remote control
 which is a LED-based product and the laser pointer to compare the two," stated
 Mr. Watson. "Which one would you rather look at?"
 
     About Plaintree Systems
     -----------------------
     Founded in 1988, Plaintree Systems Inc. is a manufacturer of optical
 wireless links, network switches, and LAN and telecommunications products.
 Using infrared LED technology, Plaintree's high-quality products offer high-
 speed data and voice transmission without any licensing requirements. These
 links are easy to install. Once installed the links are safe, secure,
 reliable, and robust. Unlike other network solutions, they can be densely co-
 located to provide high bandwidth connectivity without spectrum congestion
 problems associated with the crowded airwaves. The technology is a cost-
 efficient alternative to the expense of laying cable over the 'last mile'.
 Internet service providers and cellular operators are some of the potential
 markets for Plaintree's systems. Another high-potential market is at airports,
 where radio emissions abound and are tightly restricted.
     Plaintree Systems Inc. is headquartered in the Ottawa region and operates
 manufacturing facilities for switches and wireless products in Arnprior,
 Ontario. Plaintree is publicly traded in Canada on the Toronto Stock Exchange
 and in the U.S. on the Nasdaq Bulletin Board, with 86,059,869 shares
 outstanding. Plaintree maintains a worldwide web site at
 http://www.plaintree.com.
 
     This press release may include statements that are forward-looking and
 based on current expectations. The actual results of the company may differ
 materially from current expectations. The business of the company is subject
 to many risks and uncertainties, including changes in markets for the
 company's products, delays in product development and introduction to
 manufacturing and intense competition. For a more detailed discussion of the
 risks and uncertainties related to the company's business, please refer to
 documents filed by the company with the U.S. Securities and Exchange
 Commission and Canadian regulatory authorities, including the company's
 prospectus dated July 10, 2000.
 
 SOURCE Plaintree Systems Inc.