Nortel ISDN Signaling Link, Description, Installation And Operation

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Description Page 69 of 378
ITG Trunk 2.0 ISDN Signaling Link (ISL) Description, Installation and Operation
G.729
The G.729B codec use compression at 8 kbit/s (8:1 compression rate).
Optional Annex B Voice Activity Detection/Silence Suppression is
configurable through MAT. Only 16 channels per card are supported with
G.729B due to higher DSP resources required for this codec.
G.723.1 (5.3 kbit/s or 6.3 kbit/s)
The G.723.1 codec provides the greatest compression. Voice Activity
Detection/Silence Suppression is configurable through MAT. 24 channels per
card are supported with G.723.1.
Three downloadable DSP profiles support the codecs shown in Table 4.
Each codec supports one of three sets of parameters: one for DSP, one for fax,
and one for codec.
Table 4
Codecs supported by the ITG
Profile 1
32 ms. Echo Cancel Tail
24 ports/card Profile 2
32 ms. Echo Cancel Tail
24 ports/card Profile 3
32 ms. Echo Cancel Tail
16 ports/card
PCM A-law (G.711) PCM A-law (G.711) PCM A-law (G.711)
PCM
µ
-law (G.711) PCM
µ
-law (G.711) PCM
µ
-law (G.711)
G.729AB G.723.1 5.3 kbit/s G.729B
Clear Channel G.723.1 6.3 kbit/s Clear Channel
Fax Clear Channel Fax
Fax