Cisco Proximity Ultrasound Signal - Cisco Desk User Manual

Cisco Proximity

Cisco Proximity ultrasound signal

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 effects for some
individuals, it is very unlikely that any effects 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 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.
Animals like dogs will hear the proximity signal, since their
frequency range of hearing is so much wider.
15505.01 Cisco Desk Series User Guide JANUARY 2023
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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 Cisco Proximity
The Cisco Proximity feature allows
you to share content from a
computer wirelessly on a Cisco
device. You can even use your own
smart phone, tablets, PC or MAC
to control calls on the video device.
Observe the following:
You 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, some, or all of the
available features.
Proximity uses ultrasound to
connect users (more at left). Don't
block the microphone on your
computer, phone or tablet.
Proximity doesn't work outside
meeting rooms when doors are
closed. You need to be close to the
video endpoint to use Proximity.
For privacy, keep meeting room
doors closed to avoid possible
eavesdropping.
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