Mitel 3300 Technician's Handbook page 205

Table 46. Troubleshoot Audio Quality Problems
Symptoms
Distorted audio only
on NSU
Broken Audio,
intermittent
Broken Audio,
intermittent
Broken Audio,
intermittent
Probable cause
Voice encoding is not
inverted.
Handsfree on the far
end.
Packet loss, jitter via
network.
Limited bandwidth and
too many calls across
router, or combination
data and voice.
Troubleshooting
Corrective Action
1.
For T1, enable invert
for Voice encoding in link
descriptor.
2.
For CEPT or API,
enable ADI invert for
voice encoding.
Ensure that neither
device is using
Handsfree. Some
handsfree phones
only operate at half
duplex.
1.
Identify the speech
path between the two
end points, including
router, switch WAN in the
audio stream.
2.
The network
administrator needs to
apply QOS/TOS to
minimize jitter over slow
speed interface (T1,
Frame Relay, etc.), and
give voice traffic priority
over data.
1.
Limit the number of
calls to remote subnets.
2.
The network
administrator needs to
apply QOS/TOS to give
voice traffic priority over
data.
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