Specifications

Chapter 17 – Audio Commands
Multi-Tech Systems, Inc. AT Commands for EDGE Modems (S000371B) 217
17.9 AT^SNFA Set or Query of Microphone
Attenuation
Description: AT^SNFA specifies the large-scale attenuation on the microphone path of the audio
device currently selected with AT^SNFS. The write command is only available in audio
modes 2 to 6.
Test Command: AT^SNFA=?
Response: ^SNFA: (list of supported <atten>s)
OK
Read Command: AT^SNFA?
Response: ^SNFA: <atten>
OK
Write Command: AT^SNFA=<atten>
Response: OK
ERROR
CME ERROR: <err>
Parameter Description:
<atten>
Multiplication factor for input samples. Parameter <atten> is identical with <inCalibrate> of AT^SNFI.
Formula used to calculate microphone attenuation (negative gain):
Gain in dB = 20 * log(<atten>/32768)
0.....65535 Default = 32767
0 Microphone is muted.
Please note that AT^SNFA cannot be used to mute the microphone. Therefore, any attempt to
enter 0 will be rejected and an error response will be given. Value 0 is returned only by the read
command AT^SNFA? after the microphone was muted with AT^SNFM=0 during an active call.
32767 No attenuation on the microphone path.
Values greater than 32767 will be suppressed to 32767.
Notes:
• This command is provided for compatibility with former products and is a subset of AT^SNFI. The parameter
<inCalibrate> of AT^SNFI is identical with <atten> of AT^SNFA.
• To make the changes persistent use AT^SNFW.
Example:
^SYSSTART
at^snfa=?
^SNFA: (0-65535)
OK
at^snfa?
^SNFA: 32767
OK
at^snfs=4
OK
at^snfa=1
OK
at^snfa?
^SNFA: 1
OK
at^snfi?
^SNFI: 5,1
OK
at^snfi=5,45
OK
at^snfa?
^SNFA: 45
OK