Revision: C
CA12CD Product Summary.doc
9 of 12 pages
general procedure for avoiding sidetone problems is to avoid
unnecessarily-high transmit-volume levels and to keep the sidetone
controls on the installation—if present—set to their minimum
positions. The sidetone controls may be user-accessible, or they
may be accessible only to service personnel.
The reason for minimizing sidetone from the customer equipment
is due to the delay introduced by the digital architecture (TDMA
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of the DECT radio link. Sidetone generated in the customer
equipment is delayed by about 20 mS by the time it reaches the
user’s ears. This is enough of a delay to be unpleasant to the user.
Under normal conditions, a local echo canceller in the base stops
sidetone and network-generated echoes from reaching the user, but
if the transmit signal is too high, or if there is non-linear processing
in the sidetone path, sidetone breakthrough will occur, and the user
will hear the distorted audio described above. A sidetone generator
in the remote replaces the sidetone that has been removed by the
local echo canceller.
3.2
Interference
The CA12CD shares its frequency band with other radio products.
Sometimes interference occurs due to other products using the
same band. Interference may result in buzzing or pops in the talk or
listen audio, or irregular mutes of the talk or listen audio, or may
result in shortened range. The following steps may improve the
performance of a CA12CD that is experiencing interference:
•
Repositioning the base
•
Limiting the distance between the base and the headset
while in use
•
Repositioning the interference source, if known
If the CA12CD base or remote is placed within a few inches of a
cellular phone, the CA12CD may experience interference.
Reposition the cellular phone or the CA12CD base or remote to
increase the separation if this problem occurs.
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Range and User Density
Range is as much as 100 feet. The effective limit to range is set by
the onset of audio artifacts as the user gets further away from the
base. Range can be reduced within a building by the obstruction of
interior walls, or by the presence of other equipment operating in
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Time Division Multiple Access
