INSTALLATION
Echo Canceller
The CELP Module contains an Echo Canceller. This Echo Canceller can
neutralize echo in tail circuits up to 8ms round trip delay. When the tail
circuit delay is greater than this value then an external echo canceller
must be used. Note that any echo cancellation circuitry in the tail circuit
(in the range of 0 to 8ms) e.g. in a PBX must be disabled. The CELP Echo
Canceller can not be disabled (See Table 2-11).
TABLE 2-11. OPTION SELECTIONS, CODEC TIMING
Switch (S)
Feature
Selection
Desig.
Position
Application
CODEC Timing
Source
Basecard
S2-5
OFF
This switch controls the source of timing for the
basecards CODEC IC. The CELP Plug-in always
needs to supply timing for the CODEC.
Plug-in
S2-5
ON
Therefore, this switch should always be in the “ON”
position when the CELP plug-in is present.
Not Used
S2-1
S2-2
S2-3
S2-4
S2-6
S2-7
S2-8
OFF
OFF
OFF
OFF
OFF
OFF
OFF
Echo Canceller is always enabled
2-11
