Nortel CS 1000 Manual page 34

34 Site planning and hardware deployment
•
A small incidental transmission error is not noticeable in speech.
•
A minor transmission error causes audible clicks during speech.
•
A major transmission error causes the loss of speech.
The following factors effects the voice quality as well:
•
Moving speed
The DECT techniques allow a maximum moving speed of 5 kilometers
per hour (km/h). Bear this in mind if your DECT system must cover an
elevator.
•
Metal Construction
In metal structures, reflection can negatively impact voice quality (clicks
and interruptions can occur) even if you are close to the DAP. This
effect is made worse when the handset is in motion.
For more information see
The required quality depends on the customer requirements and the
environment. The following are the various quality levels:
•
Excellent and good
In business, office, and first aid environments, the excellent and good
voice quality is required to avoid dropped calls, inherent sounds, or
pauses in important conversations. Any sounds produced by a lower
quality level noticed by the system users, because these environments
are usually quiet or produce less background noise.
•
Satisfactory
In less critical areas like basements, stock rooms, and cold stores, the
satisfactory quality level is usually accepted because they are noisy
environments. In a noisy environment people do not notice an audible
click in a conversation, because the environment produces a lot of
background noise. This environmental background noise may also
contain audible clicks. Sometimes, the voice of a user is less audible to
the other user listening at the other end of the conversation because
of the background noise.
Use the following points as general guidelines:
•
A maximum of 20 percent of the whole coverage is considered as
satisfactory.
•
Install a hard-wired emergency telephone in those areas where the
quality is satisfactory. This ensures that people can always make a call
in case of an emergency.
•
If you agree with the customer on lower speech quality, then make
sure that this is well documented and signed by the customer. If
"Coverage calculation" (page
Nortel Communication Server 1000
SIP DECT Fundamentals
NN43120-123 02.02 30 March 2010
Copyright © 2008-2010 Nortel Networks. All Rights Reserved.
35).