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Net-2000™ Voice Codec Unit
User’s Manual
Page 43
Section 3 – Net-2000™ VCU Control
DVSI Confidential Proprietary
also depends on the vocoder in use. Tables 12a and 12b lists the input flags to the encoder and the
output flags of the decoder for the cmode element of Voice packets.
cmode parameter
Encoder Input Flags
Byte 18
7 6 5 4 3 2 1 0
Byte 19
7 6 5 4 3 2 1 0
Hex Value
Noise Suppression Enable
0 0 0 0 0 0 0 0
0 1 0 0 0 0 0 0
0x0040
DTX Enable
0 0 0 0 0 1 0 0
0 0 0 0 0 0 0 0
0x0400
Tone Detection Enable
0 0 0 1 0 0 0 0
0 0 0 0 0 0 0 0
0x1000
Tone Signaling
0 1 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0x4000
Table 32 a cmode Parameter (Half-Rate Encoder Inputs)
The values in Table 12a apply only to the AMBE+2 encoder. The value of cmode should always be
zero for the AMBE / AMBE+ encoder.
cmode parameter
Decoder Output Flags
Byte 18
7 6 5 4 3 2 1 0
Byte 19
7 6 5 4 3 2 1 0
Hex Value
Voice Active
0 0 0 0 0 0 0 0
0 0 0 0 0 0 1 0
0x0002
Data Invalid
0 0 0 0 0 0 0 0
0 0 1 0 0 0 0 0
0x0020
Tone Frame
1 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0x8000
Table 32 a cmode Parameter (Half-Rate Encoder Inputs) cmode Parameter
The Data Invalid flag is set by the Decoder if the data that was received in the Channel packet used
to generate the Voice packet was invalid, or if the Lost Frame or Mute flag was set in the cmode
element of the Channel packet. The AMBE+2 decoder sets the Voice Active flag if the packet is not a
silence frame. The AMBE+2 decoder sets the Tone Frame flag if the packet contains a tone. The
values of the tone element of the packet contain the index and amplitude of the tone.
Voice Packet Bytes 20 – 23 (tone [2])
Appropriate values for tone.idx and tone.amp are the same as the tone.idx and tone.amp values for
Channel packets and are listed in Tables 8 and 9. When tone signaling is inactive tone.idx should be
set to NO TONE and tone.amp should be set to zero.
Voice Packet Bytes 24 and 25 (ws)
The ws element of the packet contains the number of voice samples that the voice packet contains.
Appropriate values for ws are listed in Table 10.
ws
= Number of voice samples.
Description
Byte 24
7 6 5 4 3 2 1 0
Byte 25
7 6 5 4 3 2 1 0
Decimal
Value
0 0 0 0 0 0 0 0
1 0 0 1 1 1 1 1
159
0 0 0 0 0 0 0 0
1 0 1 0 0 0 0 0
160
0 0 0 0 0 0 0 0
1 0 1 0 0 0 0 1
161
Table 33 ws Parameter