Polycom RMX 1500 Administrator's Manual page 182

Chapter 3-Cascading Conferences
3-18
System Flag Settings
The DTMF_FORWARD_ANY_DIGIT_TIMER_SECONDS flag
determines the time period (in seconds) that MCU A will forward DTMF
inputs from conference A participants to MCU B.
Once the timer expires, most of the DTMF codes (excluding five
operations as for IP links) entered in conference A will not be forwarded
to conference B. This is done to prevent an operation requested by a
participant individually (for example, mute my line) to be applied to all
the participants in conference B.
Flag range (in seconds): 0 - 360000
This flag is defined on MCU A (the calling MCU).
If a flag is not listed in the System Flags list it must be added to the
system.cfg file before it can be modified. For more details on defining
system flags, see "Modifying System Flags" on page 19-6.