Polycom RMX 1500 Administrator's Manual page 212

Chapter 3-Cascading Conferences
3-48
MGC running versions other than 9.0.4 is always on level 1 and must be
set as the Master MCU. If the cascading topology includes additional
MGCs as well as RMXs it is recommended to define Video Switching
conferences for all the cascading conferences in the topology.
If MGC is running version 9.0.4, and RMX is running version 7.0.2 and
higher, the MGC can be set as Master on level 1 and MGC as Slave on
level 2
Depending on the dialing direction, the following procedures must be
performed:
Table 3-7 Set up Procedures according to the Dialing Direction
Dialing
Direction
MGC to Set the appropriate flags
RMX (done once only).
Define the conference
setting and its line rate to be
the same as the one set on
the RMX.
Define the dial-out
participant (Cascaded Link)
to the conference running
on the RMX.
MGC Level 1
RMX 1500/2000/4000
Level 2
Set the appropriate flags (done
once only).
Define the cascade-enabled
Entry Queue, setting it as Slave.
Define the conference setting
and its line rate to be the same
as the one set on the MGC.