A LAN (Local Area Network) connects host computers and information processing terminals in offices, factories etc. It also connects terminals mutually.
Safety, Health and Injury Management and Wellbeing
CISCO Wireless LAN Safety Precautions ref. 1
Proper operation according to the instructions will result in user exposure that is substantially below the FCC recommended limits OET-65, ANSI C95.1, 1991, ETS 300.328
- Do not touch or move antenna while transmitting or receiving.
- Do not hold any component containing a radio such that the antenna is very close to or touching any exposed parts of the body, especially the face or eyes, while transmitting.
- Do not operate a portable transmitter near unshielded blasting caps or in an explosive environment.
- Do not operate the radio or attempt to transmit data unless the antenna is connected; otherwise, the radio may be damaged.
- Orient antenna so that it is at least 20 cm from your body.
Wireless LAN Systems
- Peak transmitted power 32 mW, 2.4 GHz – (20 x less than mobile phone) (< 1mW/cm2 at 3 cm)
- Average power is less
- Isotropic (low gain antenna)
- Mobile phones 600 mW to 2 Watt
- Proximity - usually minimum of 1 m
- Complies with ACA guidelines sidebands 95 dB down
- Transmitting intermittently in bursts - (100 Mbytes/day is 10 min of transmission time)
Reference levels for exposure to instantaneous RMS electric and magnetic fields (unperturbed fields) ref. 2
| Exposure category | Frequency range | E-field strength (V/m rms) | H-field strength (A/m rms) | Equivalent plane wave power flux density Seq (W/m2) |
|---|---|---|---|---|
| Occupational | ||||
| 100kHz-1kHz | 614 | 1.63/f | - | |
| 1MHz-10Mhz | 614/f | 1.63/f | 1000 / f2 (see note 5) | |
| 10MHz-400Mhz | 61.4 | 0.163 | 10 (see note 5) | |
| 400MHz-2GHz | 3.07xf0.5 | 0.00814xf0.5 | f/40 | |
| 2GHz-300Ghz | 137 | 0.364 | 50 | |
| General public | ||||
| 100kHz-150kHz | 86.8 | 4.86 | - | |
| 150kHz-1MHz | 86.8 | 0.729/f | - | |
| 1MHz-10MHz | 86.8/f0.5 | 0.729/f | - | |
| 10MHz-400Mhz | 27.4 | 0.729 | 2 (see note 6) | |
| 400MHz-2GHz | 1.37xf0.5 | 0.00364xf0.5 | f/200 | |
| 2GHz-300GHz | 61.4 | 0.163 | 1 |
Radiation Protection Standard 2002 Australia Maximum Exposure Levels to Radiofrequency Fields - 3 kHz to 300 GHz
Wireless LAN Standard – 802.11 ref. 1
| Data Rate | Maximum EIRP for IEEE 802.11b with 0-dBi Antenna Gain | ||
|---|---|---|---|
| mW | dBm | ||
| IEEE 802.11a | 6 -24 Mbps | 40 | 16 |
| IEEE 802.11a | 48 - 54Mbps | 20 | 13 |
| IEEE 802.11b | 1 - 11Mbps | 100 | 20 |
| IEEE 802.11g | 6 - 24 Mbps | 50 | 17 |
| IEEE 802.11g | 36 Mbps | 40 | 16 |
| IEEE 802.11g | 48 Mbps | 31.6 | 15 |
| IEEE 802.11g | 54 Mbps | 20 | 1 |
Other wireless LAN standards:
- HiperLan
- HiperLan II
- OpenAir
- HomeRF
- SWAP
BlueTooth is cable replacement and not wireless LAN.
Wireless LAN Systems Questions and Answers
Can you absolutely assure customers that Wireless LAN products are safe?
Extensive research on the safety of exposure to radio frequency electromagnetic energy has been carried out for more than four decades. This research is continually reviewed and interpreted by committees of scientists who develop safe limits for exposure. Manufacturers of wireless LANs monitor this research and participate in the consensus standards process and ensure that WLAN products operate within the guidelines of these standards. Consequently, manufacturers of WLAN products believe their products are safe.
What if the network has 100 nodes?
Only one transmitter is active at any point in time, so the radiated power of a total network even when it has 100 nodes is actually equivalent to the radiated power of a single transmitter. WLAN transmitters operate at a power of 0.035 Watts (35 mW) in the 2.4 GHz band depending on the specific product in use and the local regulations.
How does WLAN technology differ from cellular technology?
WLAN products use a "bursty" type of transmit/receive protocol, while Cellular transmits and receives constantly (connection oriented). As an example: If a user would transfer data on an average of 100 MB per day, the WLAN transmitter would be on the air for approximately 10 minutes. Moreover, a typical hand held-cell phone has a RF power output of 0.600 Watts (600 mW) or almost 20X more output power!
Wireless LAN Systems Conclusion
Safe, Low-Power Radiation
Wireless LAN (WLAN) devices emit radio frequency electromagnetic energy. Because WLANs are designed to operate within the guidelines found in radio frequency safety standards and recommendations, WLANs are safe for use by consumers. These standards and recommendations reflect the consensus of the scientific community and result from deliberations of panels and committees of scientists who continually review and interpret the extensive research literature.
Conclusion
The interpretation of over four decades of research in this area has led to a scientific consensus on the safety of exposure to radio frequency electromagnetic fields. This consensus is reflected in the recommendations and standards developed by expert committees such as NCRP Scientific Committee 53, IEEE Standards Coordinating Committee 28, IRPA/INIRC and NRPB. Manufacturers of Wireless Networking products design their products to operate within the guidelines of these standards and recommendations and, therefore, are considered safe.
University information
CRICOS Code: 00126G
