15435.02 Cisco Webex Desk Pro User Guide JUNE 2020
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24
Intelligent Proximity
Cisco Proximity Ultrasound Signal
Intelligent Proximity
About Proximity
Cisco devices emit ultrasound as part of the
Proximity feature. Most people are exposed
to ultrasound more or less daily in many
environments, including industry, commercial
applications, and home appliances.
Even if airborne ultrasound may cause subjective
eects for some individuals, it is very unlikely that
any eects occur for sound pressure levels below
75 dB. Guidelines for ultrasound exposure limits vary
heavily between countries, but 75 dB is the lowest
limit presently found for the frequency band around
20 kHz, which is where the Cisco proximity signal is
emitted.
A good reference for this information is Health
Canada´s guidelines, http://www.hc-sc.gc.ca/
ewh-semt/pubs/radiation/safety-code_24-
securite/index-eng.php#a2.2.2.
These guidelines state that sound pressure levels
lower than 120 dB have not been demonstrated
to cause hearing loss, neither permanently nor
temporarily.
For Cisco devices for personal use the ultrasound
sound pressure level is below 70 dB at a distance
of 20 cm or more from the loudspeaker.
In most practical cases the level at the ear of
the user will be much lower than these max
levels, due to loudspeaker directivity, distance
attenuation, and high degree of high frequency
absorption in typical rooms. The levels will range
from what for audible sound would be typical
background / ambient noise levels in meeting
spaces up to so-called conversational levels of
normal speech.
It is therefore deemed safe for humans to be
continuously subjected to the proximity signal.
Most people will not be aware of the presence
of the signal, and suer no eects from it. A few
individuals with especially acute high frequency
hearing can, however, be able to hear it, this is
most likely to happen directly in front of and close
to the loudspeaker.
It is obvious that animals like dogs will hear the
proximity signal, since their frequency range of
hearing is so much wider.
However, the eect of sound is also level
dependent, and the level range of a dog´s hearing
is not signicantly dierent from that of a human.
The hearing threshold of dogs at 20 kHz can be
as low as 0–10 dB, similar to the threshold of a
human ear in its most sensitive frequency range.
Cisco has not done testing or qualication of the
possible eects the signal can have on dogs. Due
to the limited levels it is believed that while the
signal is clearly audible, it is not bothersome to
dogs.
A dog in an oce or meeting room will be subject
to ultrasound at levels comparable to normal
background noise, or at most conversational
levels. There has been no reports of animals
being bothered by the signals in the years we
have had this feature in our products.
However, the question of ultrasound eect on
dogs is fair, since dog repeller devices using
ultrasound do exist. These devices typically claim
to use discomforting, but not harmful ultrasound.
Cisco does not have insight into dog repeller
design, but scanning the specications of such
devices typically reveals that the exposure levels
typically are 100 dB and upwards.
For solutions using Cisco video codecs with 3rd
party loudspeaker systems Cisco is not able to
control the ultrasound sound pressure level. In
most cases the necessary loudspeaker sensitivity
and frequency response will result in levels below
the 75 dB limit. However, if excessive external
amplication is applied, or the loudspeaker
system has an emphasized high-frequency
response, levels in excess of the limit can be
produced.
The Intelligent Proximity feature allows
you to share content from a computer
wirelessly on the device. Smart
phones and tablets are also able to
view the shared content directly on
their own screens.
You can even use your own smart
phone, tablets, PC or MAC to control
calls on the device.
Observe the following:
You can download the Cisco Intelligent
Proximity app from App Store or
Google Play (free of charge).
Windows or OS X users, go to
https://proximity.cisco.com/.
Your video support team may have
activated none of the features, all of
them, or just a subset of them.
Intelligent Proximity makes use of
ultrasound when connecting users
(see more at left). Do not block the
microphone of your computer, smart
phone, or tablet.
Intelligent Proximity has been designed
not to work outside the meeting
room when doors to the room are
kept closed. You need to be in close
proximity of the video device to use
the feature.
When privacy dictates, always keep the
meeting room entrance doors closed
to avoid possible eavesdropping from
adjacent rooms.
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