Polycom WEBCOMMANDER 8 - Manual (Page 238)

MGC WebCommander User’s Guide
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The LSD channel is allocated from the video channel bandwidth, resulting in
a lower line rate for the conference. In a Video Switching conference, if an
endpoint does not support LSD and cannot open the LSD channel, the
participant connects as audio only (Secondary). In Continuous Presence and
Transcoding conferences, endpoints that do not support LSD remain
connected in their initial line rate.
The Far End Camera Control protocol H.281 is used to control the video
camera remotely with ISDN and IP endpoints. With H.323 endpoints, Annex
Q or RV mode (Radvision proprietary method) is used for H.281 commands/
messages requesting control over the far end camera from the MCU.
In a mixed conference with IP and ISDN participants, the MCU simulates the
use of data tokens with H.323 endpoints to work in a similar way as with
ISDN endpoints. In IP and ISDN connections, a camera can control a far end
camera by requesting the control from the MCU. The MCU grants the
requesting endpoint the data token. When the data token is released by the
endpoint holding it, the token can be taken by another endpoint (IP or ISDN)
without the MCU closing the data channel or stream. If the token is not
released by the endpoint, the MGC Manager operator can also withdraw the
data token from the endpoint.
The data token management via the MCU during an On Going conference can
only be performed through the MGC Manager application (and not the
WebCommander Meeting Director). For more information, refer to the MGC
Manager User’s Guide.
For more details regarding LSD - FECC (Far End Camera Control), see the
MGC Manager User’s Guide Volume II, Chapter 1.
FECC/LSD Guidelines:
• In Video Switching conferences in which FECC/LSD is enabled, ISDN
endpoints that do not support LSD and cannot open the LSD channel
connect as Secondary (Audio only) while IP endpoints remain connected
at their initial line rate.
• In Continuous Presence and Transcoding conferences, ISDN endpoints
that do not support LSD remain connected at their initial line rate.
• In encrypted conferences with ISDN and IP participants, the FECC
channel rate is always 4.8.
• In H.320, Master/Slave cascading conferences, only the FECC/LSD 6.4
(fixed rate) option is available. In such a conference, when a request for