Intelligent Proximity; About Proximity - Cisco Webex DX70 User Manual

Intelligent Proximity

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,
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 losses, neither permanently nor
temporarily.
D1510422 User Guide
Cisco Webex DX70, DX80
Produced: September 2018 for CE9.5
All contents © 2010–2018
Cisco Systems, Inc. All rights reserved
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 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
http://www.hc-sc.gc.ca/ewh-
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.
24

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.