Vertical Communications 8412S Telephone User Manual


 
Depending on telephone line conditions and the type of speakerphone the
distant party is using, it may not be possible for the 8412F speakerphone
to operate in full-duplex mode. If the distant party’s speakerphone is a
half-duplex model and both you and the distant party are in
speakerphone mode, the half-duplex speakerphone controls the
communications mode and prevents the 8412F from operating in
full-duplex mode.
To maximize the usefullness of your full-duplex speakerphone, take note
of these following observations about full-duplex speakerphone
operation.
The full duplex operating mode requires a small amount of time to
adapt to changes in echo; therefore, you should avoid making any
movements in the vicinity—about a one-foot radius—of the
speakerphone.
There are certain echo limits beyond which the speakerphone cannot
effect canceling. These limits are as follows: room echoes beyond 39
milliseconds (standard configuration) and line echoes beyond 24
milliseconds (standard configuration).
The speakerphone may automatically reduce the volume in each
direction when both you and the distant party talk at the same time
(double-talk). This volume reduction is necessary to control the
echoes at high volume levels. It is possible for surrounding
conversations and other sounds to trigger double-talk even when you
are not speaking. This condition may lower the loudspeaker volume
at your speakerphone.
You must adjust the loudness of your voice to match that of the
distant party’s voice. This action is necessary to cause full-duplex
operation to take place. Sustained doulbe-talk or excessive echo may
cause the speakerphone to drop back into half-duplex operation. This
happens because the speakerphone’s echo cancel circuits cannot
adapt during the double-talk situation.
If both you and the distant party are using full-duplex
speakerphones, the sensitivity to both echo path changes and volume
reduction during double-talk is doubled from the sensitivity when
just one full-duplex speakerphone is involved.
1 – 4 Large Screen Speakerphone Manual
Introducing The Large Screen Speakerphone GCA70–349