Digital Voice Systems VC-20-ATC-10B, Руководство пользователя

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Section 6 – VC-20™ ATC-10b Vocoder Board Advanced Features
VC-20

ATC-10b Vocoder Board User’s Manual
page 12
The Speech Compression Specialists
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IGITAL
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OICE
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YSTEMS,
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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 MSB…LSB Freq #2 Freq #1
1 0000 1209 Hz. 697 Hz.
4 0001 1209 Hz. 770 Hz.
7 0010 1209 Hz. 852 Hz.
* 0011 1209 Hz. 941 Hz.
2 0100 1336 Hz. 697 Hz.
5 0101 1336 Hz. 770 Hz.
8 0110 1336 Hz. 852 Hz.
0 0111 1336 Hz. 941 Hz.
3 1000 1477 Hz. 697 Hz.
6 1001 1477 Hz. 770 Hz.
9 1010 1477 Hz. 852 Hz.
# 1011 1477 Hz. 941 Hz.
A 1100 1633 Hz. 697 Hz.
B 1101 1633 Hz. 770 Hz.
C 1110 1633 Hz. 852 Hz.
D 1111 1633 Hz. 941 Hz.
Table 1: DTMF Tone Data