Z02215 Datasheet, PDF (28/74 Pages) Zilog, Inc. – Single Chip Modem with Integrated Controller, Data Pump, and Analog Front End

Z02215
Single Chip Modem with Integrated Controller, Data Pump, and AFE
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Table 3. AT Command Set (Continued)
Command
#F
DTMF
Detection
Command
Function and Description
#F is used to detect DTMF digits received by the modem when it is off-hook in
the COMMAND state. #F does not operate during a data connection. The #F
command can only be entered from the command state and assumes that the
phone is off-hook. For example, to dial a call and then immediately enter the
DTMF detection mode the following series of steps are taken:
1. Send ATDxxxxx; command where xxxxx is the phone number.
2. Wait for the OK response.
3. Send AT#F1 to the modem.
4. You are now in the DTMF detection mode.
During DTMF detection the modem decodes received DTMF tones and issues
a line of ASCII text to the terminal each time a DTMF digit is detected.
DTMF Digit
0–9
*
#
A–D
Output Text
0–9
10
11
12–15
The following table describes the output text according to which pair of DTMF
high and low tones were detected.
High band/
Low band 1209 Hz 1336 Hz 1477 Hz 1633 Hz
697 Hz
1
2
3
12
770 Hz
4
5
6
13
852 Hz
7
8
9
14
941 Hz
10
0
11
15
#F0
Detect DTMF digits with out using a human speech filter.
DTMF digits as short as 50 ms can be detected.
#F1
Detect DTMF digits while using a filter that reduces the
effect of human speech on the detection of DTMF digits,
improving the accuracy of detection. DTMF digits as short
as 60 ms can be detected.
PS001907-0904
AT Command Set