Intelligent Proximity
On the Cisco Proximity Ultrasound Signal
Cisco video systems 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
effects for some individuals, it is very unlikely
that any effects will 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,
ewh-semt/pubs/radiation/safety-code_24-
securite/index-eng.php#a2.2.2.
D1509716 User Guide
Cisco TelePresence SX10, SX20
Produced: September 2018 for CE9.5
All contents © 2010–2018
Cisco Systems, Inc. All rights reserved.
These guidelines state that sound pressure levels
lower than 120 dB have not been demonstrated
to cause hearing losses, neither permanently nor
temporarily.
For Cisco video systems for group use with
integrated loudspeakers the ultrasound sound
pressure level is below 75 dB at a distance of
50 cm or more from the loudspeaker.
For Cisco video systems for personal use
the ultrasound sound pressure level is below
70 dB at a distance of 20 cm or more from the
loudspeaker.
For Cisco WebEx Boards the ultrasound sound
pressure level is below 75 dB at a distance of
http://www.hc-sc.gc.ca/
20 cm or more in front of the display. The level
can be slightly higher right below the display due
to the downward-facing loudspeakers.
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
continously subjected to the proximity signal.
Most people will not be aware of the presence
of the signal, and suffer no effects 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 effect of sound is also level
dependent, and the level range of a dog´s
hearing is not significantly different 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 qualification of the
possible effects 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 office 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 effect 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 specifications 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 amplification is applied, or the
loudspeaker system has an emphasized high-
frequency response, levels in excess of the limit
can be produced.
About Proximity
The Intelligent Proximity feature
allows you to share content from a
computer wirelessly on the video
system. 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 video system.
Observe the following:
You will need to download (free
of charge) the Cisco Intelligent
Proximity app from App Store or
Google Play.
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 will need
to be in close proximity of the video
endpoint 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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