Channel Packet Bytes 18 And 19 (Cmode); Table 18 A Cmode Channel Parameter (Decoder Input Flags) - Digital Voice Systems Net-2000 User Manual

Net-2000™ Voice Codec Unit
User's Manual
9600
4850 4750
9600
3600 6000
9600
2400 7200
9600
3600 6000
2400 7200
Table Key
AMBE-1000 Compatable Rates
AMBE-20xx Compatable Rates
AMBE+2 Compatable Rates

Channel Packet Bytes 18 and 19 (cmode)

The cmode element of the Channel packet contains the input flags to the decoder when it is
transmitted to the VCU and the output flags of the encoder when it is transmitted by the VCU. The
value of cmode also depends on the vocoder in use. Tables 12a and 12b list values for the decoder
input and encoder output flags of the Channel packet.
Cmode parameter
Decoder Input Flags
Nominal Value
Lost Frame
Mute
Tone Signaling

Table 18 a cmode Channel Parameter (Decoder Input Flags)

The nominal value for the cmode parameter should be zero when transmitting Channel packets to the
VCU. To get the decoder to perform a frame repeat set the Lost Frame flag. To generate comfort
noise (i.e., mute) set the Mute flag. The Tone Signaling Flag can be set to get the AMBE+2 vocoder
to ignore the channel data in the packet and generate a tone. The index and amplitude of the tone
should be set in the tone[] parameter of the Channel packet. The a-Law and U-Law decoders do
not support tone signaling and ignore this flag.
Cmode parameter
Encoder Output Flags
Voice Active
VAD
Tone Frame
Table 18 a cmode Channel Parameter (Decoder Input Flags)
When the VCU transmits Channel packets in response to Voice packets it sets the cmode parameter
with the flags returned by the encoder. The Voice Active flag is set when the packet must be
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0 0xbfc0 0x0000
0xab16 0xe400
0 0x7fc0 0x0000
0x5048 0x000e
0x1030 0x000e
0 0x04c0 0x0986
0x0448 0x0986
0x0430 0x0986
0x0000 0x0000
0x0000 0x0000
0x0000 0x0000
0x4010 0x6a2e
0x681a 0x511b
0x0000 0x0000
0x000e 0x4010
0x000e 0x681a
Byte 18
7 6 5 4 3 2 1 0 7 6 5 4 3 2 1 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0
0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0
0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Byte 18
7 6 5 4 3 2 1 0 7 6 5 4 3 2 1 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0
0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Section 3 – Net-2000™ VCU Control
0x72c0 0xc0c0
0x67c0 0xc0c0
0x69c0 0xc0c0
0x65c0 0xc0c0
0x76c0 0xc0c0
0x0000 0xc1c0
0x6a2e 0xc1c0
0x511b 0xc1c0
Byte 19
Hex Value
0x0000
0x0004
0x0008
0x4000
Byte 19
Hex Value
0x0002
0x0400
0x8000
4
6
21
30
29
53
62
61
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