ClearOne AP400 - Manual (Page 32)

Installation ~ LCD Programming 28
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G-Link reference
This bus provides a system-wide echo canceller reference signal. When multiple AP
units are linked together and will be using only one output channel to drive the
speaker system, that output must be defined as the sample reference which will be
used by all of the linked AP units for echo cancellation. It allows the reference signal
to be passed to additional G-Linked mic channels and their associated echo
cancellers. For echo cancellation to function properly, the output that the master unit
will use as the EC reference must be identified to the slave units through the G-Link
(see Figures 2.22 and 2.23 for Routing configuration). The following example
illustrates the echo cancellation setup necessary to communicate the EC reference
from the master unit to the slave unit:
“Define EC Ref and PA” tells the master unit which output (in this case output D)
will be used as the reference for echo cancellation for the master unit. This output
(D) must also be defined as the “G-Link EC Ref bus” which slave units will refer to
when you are defining their EC references (see Figure 2.22).
Slave unit
Because the slave unit will not usually be using one of its own outputs as the EC
reference, “EC Ref and PA” should be defined as the “G-Link EC Ref” only (as
shown in Figure 2.23). The slave unit will then use the master’s defined output (in
this case, Output D) as its reference for echo cancellation.
Figure 2.22. EC setup for multiple units to one output (master-unit example matrix)
Figure 2.23. EC Setup for multiple units to one output (slave-unit example matrix)