Digital Voice Systems AMBE-1000 Implementation Manual

The Speech Compression Specialists
Implementing the AMBE-2000/2020™ Vocoder Chip
at Data Rate 2350 bps Voice and 50 bps FEC
for Compatibility with the AMBE-1000™ Vocoder Chip
This white paper describes the procedure for implementing the AMBE-2000/2020™ in a
special mode that is compatible to AMBE-1000™ Vocoder Chip at 2350 bps voice and 50
bps FEC.
This procedure is ONLY required when interoperating with the AMBE-1000™ Vocoder Chip
at this specific rate (2350 voice + 50 bps FEC). All other rate configurations function as
described in the AMBE-2000/2020™ Vocoder Chip Manual.
When implementing this compatible mode on the AMBE-2000/2020™ Vocoder Chip if the
data rate is fixed and does not change, it is recommended to set the rate via the Rate_Sel
configuration pins (Pins 74, 73 72, 71, 70) as shown in Table 1. By hardwiring these pins the
procedure outlined below can be avoided.
AMBE-2000/2020™ Rate Selection Using Hardwired Rate Info 0-4, compatible w/ AMBE-1000™
RATE_SEL4 RATE_SEL3
Pin 74 Pin 73
0 0
Table 1.

Compatible Mode Procedure Step 1.

To enable the AMBE-2000/2020™ to interoperate with the AMBE-1000™ Vocoder Chip at
the rate of 2350 bps voice + 50 bps FEC, first send the packet described in Table 2.
Word # Value
0 0x13ec
1 0x0002
2 0x902f
3 0x0000
4 0x0000
5 0x0000
6 0x6930
7 0x0000
8 0x0000
9 0x0000
10 0x0000
11 0x0000
12-23
Table 2.
1 2
Page of
234 Littleton Road
Westford, MA 01886
RATE_SEL2 RATE_SEL1
Pin 72 Pin 71
1 0

First Packet

Description
Header
Power Control ID/Control Word 1
Rate 0
Rate 1
Rate 2
Rate 3
Rate 4
Unused
Unused
Unused
DTMF Control
Control Word 2
Channel Data for AMBE® voice decoder
Tel: (978) 392-0002
Fax: (978) 392-8866
RATE_SEL0 Speech Rate
Pin 70 (bps)
1 2350
email: info@dvsinc.com
web: www.dvsinc.com
Total Rate
FEC Rate (bps)
(bps)
50 2400
June 2004