1. Video telephony channel
There are 4 channel in 3G-324:
 Control channel
Voice channel
Audio channel
Video channel

2. Channels
• Control channel
 3G-324M uses H.245 as a terminal control protocol.
 H.245 requires the numbered simple retransmission protocol
(NSRP) and control channel segmentation and reassembly
layer (CCSRL) sublayer support to ensure reliable operation.
 H.245 call control with the CCRL and NSRP to assure that the
H.245 channel will be highly reliable and can use large packets
during operation..

3. H.245
• Master-slave determination is provided to determine which terminal is the
master at the beginning of the session.
• Capability exchange is provided to exchange terminal capabilities, such as
optional modes of multiplexing, type of audio/video codecs, data sharing
mode and its related parameters, and/or other additional optional features.
• Logical channel signaling is provided to open/close the logical channels for
media transmission.
• Round-trip delay measurement is provided to enable accurate quality
characteristic measurement.

4. Voice Channel—The AMR Codec
• The 3G-324M specifications define the AMR codec as
mandatory. 3G-324M also recommends the use of
G.723.1, which is used by many H.323 terminals today.
• The AMR codec was originally developed and
standardized by ETSI for GSM cellular systems.
• Optimized for mobile networks, it dynamically adjusts the
amount of bits allocated to voice coding and error
control, providing the best possible voice quality based on
radio conditions
• Another benefit of AMR is the adaptive rate adaptation
for switching smoothly between codec modes on the fly.

5. Table list a number of channels audio

6. The video channel
• MPEG-4 (ISO/IEC 14496-2) : Is a method of
defining compression of audio and visual (AV)
digital data.
• H.263 : Is a video compression standard
originally designed as a low bitrate compressed
format for videoconferencing.
• The 3G-324M standard specifies the H.263
codec as mandatory, with MPEG-4 as a
recommended codec for video processing. H.263
is a legacy codec that is used by many existing
H.323 wireline devices

7. MPEG-4 interface to multiplex
• MPEG-4 is much more flexible and offers advanced
error detection and correction services, which are a
big value add when delivering video over a wireless
network.
• Provides error resilience (through data
partitioning, RVLC, resynchronisation marker, and
header extension code) and low complexity.

8. The table lists a number of video
channels 3G-324m