Ata - Digital Voice Systems VC-20-ATC-10B User Manual

Section 6 – VC-20™ ATC-10b Vocoder Board Advanced Features
3.7 VC-20-ATC-10b DTMF Tone Data
The VC-20-ATC-10b supports DTMF detection, transmission, and generation. The
encoder detects and transmits DTMF tones, and the decoder decodes and generates
DTMF tones, in support of standard telephony requirements
In addition, if the VC-20™ - ATC-10b encoder detects a DTMF tone it activates the
DTMF_DET signal for four clock cycles of TXCK and simultaneously outputs (LSB first)
four bits of data on DTMF_DAT which identify the DTMF tone which was detected.
The DTMF_DET flag is only output once for each continuous DTMF tone that is
detected. The correspondence between the data bits and DTMF tone is shown in Table
1.
DTMF_DAT
Keypad Character
1
4
7
*
2
5
8
0
3
6
9
#
A
B
C
D
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MSB...LSB
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
Table 1: DTMF Tone Data
D V
IGITAL OICE
The Speech Compression Specialists
Freq #2 Freq #1
1209 Hz. 697 Hz.
1209 Hz. 770 Hz.
1209 Hz. 852 Hz.
1209 Hz. 941 Hz.
1336 Hz. 697 Hz.
1336 Hz. 770 Hz.
1336 Hz. 852 Hz.
1336 Hz. 941 Hz.
1477 Hz. 697 Hz.
1477 Hz. 770 Hz.
1477 Hz. 852 Hz.
1477 Hz. 941 Hz.
1633 Hz. 697 Hz.
1633 Hz. 770 Hz.
1633 Hz. 852 Hz.
1633 Hz. 941 Hz.
VC-20 ATC-10b Vocoder Board User's Manual
S I
YSTEMS, NC.