Net-2000™ Voice Codec Unit
User’s Manual
Page 30
Section 3 – Net-2000™ VCU Control
DVSI Confidential Proprietary
short len;
short type;
short seq;
short rate[5];
short cmode;
short tone[2];
short ws;
short format;
char channel[192];
};
Note that each bit of channel data occupies one byte of the channel[] buffer in the packet.
The remaining bytes in the
channel[]
buffer are ignored. The elements of the Decode
packet are described in detail in the following sections.
Channel Packet Parameters
Channel Packet Bytes 0 and 1 (len)
The len parameter (bytes 0 and 1) hold the 16-bit length of the packet (Table 3). The packet length is
always 218 bytes.
len
=
Length (in bytes) of total packet (including header)
Byte 0
7 6 5 4 3 2 1 0
Byte 1
7 6 5 4 3 2 1 0
Decimal
Value
Data Packet Size
0 0 0 0 0 0 0 0
1 1 0 1 1 1 0 0
220 bytes
Table 14 Channel Packect len header parameter
Channel Packet Bytes 2 and 3 (type)
The type parameter (bytes 2 and 3) is 16-bits packet type and is always 0x003 for channel data.
type
=
Packet type
Byte 2
7 6 5 4 3 2 1 0
Byte 3
7 6 5 4 3 2 1 0
Hex Value
Channel Data
0 0 0 0 0 0 0 0
0 0 0 0 0 0 1 1
0x0003
Table 15 type header parameter
Channel Packet Bytes 4 and 5 (seq)
Bytes 4 and 5 hold the 16-bit sequence number (see Table 5). The sequence number is used as a
method to detect if and when data packets are dropped, so it is important to ensure that consecutive
sequence numbers are transmitted for channel data packets during operation.