User`s manual

VC-55™ PR Voice Codec Board
User’s Manual Version 1.3
Section 4 – Interface Protocol
Page 16
DVSI Confidential Proprietary
rate
Byte 1 is used to set the rate information of the data in the packet.
The AMBE APCO PROJECT 25 coder runs in either one of two rates as shown in Table 9 Vocoder
Rate .
rate (vocoder rate)
Byte 1
7 6 5 4 3 2 1 0
Hex Value
Full-Rate (7200 bps) 1 1 1 1 0 0 0 0 0xF0
Half-Rate (3600 bps) 0 0 0 0 1 1 1 1 0x0F
Table 9 Vocoder Rate Elements
Rate Number of Compressed
voice data bits
Total Number of
channel data bytes
Rate (7200 bps) 144 20
Half-Rate (3600 bps) 72 11
Table 10 Rates Description