Citel 6000 Guía Del Usuario
PBXgateway
™
& EXTender
TM
6000 System Administrator’s Guide
162
Echo Problems
Understanding and Correcting Echo Problems
The PBXgateway and both EXTender 6000 and 4000 employ the industry standard G.165 echo canceller
with some proprietary MCK improvements to help eliminate or reduce echo even further. However, it is
not possible to cancel all instances of echo 100% of the time. It should be noted that echo perceived by
extended PBX users, will not be perceived by the party on the other end of the call.
The PBXgateway and both EXTender 6000 and 4000 employ the industry standard G.165 echo canceller
with some proprietary MCK improvements to help eliminate or reduce echo even further. However, it is
not possible to cancel all instances of echo 100% of the time. It should be noted that echo perceived by
extended PBX users, will not be perceived by the party on the other end of the call.
EXTender’s Impact on Echo
Because EXTenders deal exclusively with digital audio on the line side of a PBX, they cannot cause any
echo. However, if you experience any echo from your connection to the PSTN (Public Switched
Telephony Network), the EXTender application could make it noticeable because of increased delay in
the audio path. For example, if echo occurs on a line after only a few milliseconds, your ear cannot
detect the echo. However, if the echo occurs after 100, 50, or even 20 milliseconds, your ear will likely
detect the problem. The G.165 echo canceller can cancel echo up to certain limitations. If you have a
noticeable echo problem, you should look into the following:
If you experience echo on all external calls, you probably have a problem with your PSTN trunk lines.
Most likely they are analog, and those analog lines are generating a great deal of echo when interfacing
with your PBX. Non-extended PBX phones may not perceive the echo, due to the fact that echo without
delay, does not sound like echo.
Cause: The most common cause of consistent echo on all external calls, are analog trunk lines that are
out of specification, or a problem with the termination within the PBX. Most commonly there is an
impedance mismatch between the analog line and your PBX. Also, the db level of the analog circuit may
be too high. Analog circuits that are “hot” are a common cause of echo. Again, that echo may not be
perceived on non-extended phones, but that is only because there is no delay.
Possible Solution: If you have analog lines, you should consult your local phone company and ask for
the exact specifications of that line. They may need to go onsite to measure the characteristics of your
analog circuits.
If you only experience echo occasionally on external calls, your system is probably fine. The echo
probably only occurs when calling to or receiving calls from a party that is using a) analog lines, b) a cell
phone, or c) analog trunks on their phone system. In this case there is little you can do. The echo
canceller included with the EXTenders usually will cancel this echo after a second or two, but
occasionally the echo goes beyond its capabilities. However, it should be noted that the party on the
other end of the call will not experience this echo.
If you experience a slight echo on all external calls, but it goes away after a second or two, that is normal
with analog trunk lines. If you have analog trunks into your PBX, the echo canceller frequently takes a
second or two to detect levels of what is echo and what is voice. Then it starts to cancel the echo. The
only way to improve that situation is to replace your analog trunks with digital trunk lines.
echo. However, if you experience any echo from your connection to the PSTN (Public Switched
Telephony Network), the EXTender application could make it noticeable because of increased delay in
the audio path. For example, if echo occurs on a line after only a few milliseconds, your ear cannot
detect the echo. However, if the echo occurs after 100, 50, or even 20 milliseconds, your ear will likely
detect the problem. The G.165 echo canceller can cancel echo up to certain limitations. If you have a
noticeable echo problem, you should look into the following:
If you experience echo on all external calls, you probably have a problem with your PSTN trunk lines.
Most likely they are analog, and those analog lines are generating a great deal of echo when interfacing
with your PBX. Non-extended PBX phones may not perceive the echo, due to the fact that echo without
delay, does not sound like echo.
Cause: The most common cause of consistent echo on all external calls, are analog trunk lines that are
out of specification, or a problem with the termination within the PBX. Most commonly there is an
impedance mismatch between the analog line and your PBX. Also, the db level of the analog circuit may
be too high. Analog circuits that are “hot” are a common cause of echo. Again, that echo may not be
perceived on non-extended phones, but that is only because there is no delay.
Possible Solution: If you have analog lines, you should consult your local phone company and ask for
the exact specifications of that line. They may need to go onsite to measure the characteristics of your
analog circuits.
If you only experience echo occasionally on external calls, your system is probably fine. The echo
probably only occurs when calling to or receiving calls from a party that is using a) analog lines, b) a cell
phone, or c) analog trunks on their phone system. In this case there is little you can do. The echo
canceller included with the EXTenders usually will cancel this echo after a second or two, but
occasionally the echo goes beyond its capabilities. However, it should be noted that the party on the
other end of the call will not experience this echo.
If you experience a slight echo on all external calls, but it goes away after a second or two, that is normal
with analog trunk lines. If you have analog trunks into your PBX, the echo canceller frequently takes a
second or two to detect levels of what is echo and what is voice. Then it starts to cancel the echo. The
only way to improve that situation is to replace your analog trunks with digital trunk lines.