Gemalto M2M GmbH MC56 User Manual

Page of 104
MC55/56 Hardware Interface Description 
Confidential / Preliminary 
s
 
MC55/56_hd_v03.00 
Page 87 of 104 
16.08.2005 
5.5.3 
Characteristics of audio modes 
The electrical characteristics of the voiceband part depend on the current audio mode set 
with the AT^SNFS command. 
Table 29: Voiceband characteristics (typical) 
Audio mode no. 
AT^SNFS= 
(Default 
settings, not 
adjustable)  
Name 
Default 
Handset 
Basic 
Handsfree 
Headset 
User 
Handset 
Plain 
Codec 1 
Plain  
Codec 2 
Purpose 
DSB with 
Votronic 
handset 
Siemens Car 
Kit Portable 
Siemens 
Headset 
DSB with 
individual 
handset 
Direct 
access to 
speech 
coder 
Direct 
access to 
speech 
coder 
Gain setting via AT 
command. Defaults: 
 inBbcGain 
 outBbcGain 
Fix 
 
4 (24dB) 
1 (-6dB) 
Adjustable 
 
2 (12dB) 
1 (-6dB) 
Adjustable 
 
5 (30dB) 
2 (-12dB) 
Adjustable
 
4 (24dB) 
1 (-6dB) 
Adjustable 
 
0 (0dB) 
0 (0dB) 
Adjustable
 
0 (0dB) 
0 (0dB) 
Default audio 
interface 
3)
 
Power supply 
ON (2.65V) 
ON (2.65V) 
ON (2.65V) 
ON (2.65V) OFF (GND)  OFF (GND)
Sidetone 
ON 
--- 
Adjustable 
Adjustable  Adjustable  Adjustable 
Volume control 
OFF 
Adjustable 
Adjustable 
Adjustable  Adjustable  Adjustable 
Limiter (receive) 
ON 
ON 
ON 
ON 
--- 
--- 
Compressor 
(receive) 
--- 
OFF
1)
 
--- 
--- 
--- 
--- 
AGC (send) 
--- 
--- 
ON 
--- 
--- 
--- 
Echo control (send)  Suppression  Cancellation +
suppression 
--- 
Suppres-
sion 
--- 
--- 
Noise suppression
2)
  --- 
up to 10dB 
10dB 
--- 
--- 
--- 
MIC input signal for 
0dBm0 @ 1024 Hz 
(default gain) 
23mV 
58mV 
7.5mV @ 
-3dBm0 due 
to AGC 
23mV 
315mV 
315mV 
EP output signal in 
mV rms. @ 0dBm0, 
1024 Hz, no load 
(default gain); 
@ 3.14 dBm0 
284mV 
120mV 
default @ 
max volume 
300mV 
default @ 
max volume 
284mV 
default @ 
max 
volume 
895mV 
 
 
3.7Vpp 
895mV 
 
 
3.7Vpp 
Sidetone gain at 
default settings 
22.8dB 
-∞ dB 
Affected by 
AGC, 13dB 
@ 7.5mV 
(MIC) 
22.8dB 
-∞ dB
 
-∞ dB
 
 
1)
  Adaptive, receive volume increases with higher ambient noise level. The compressor can be 
activated by loading an application specific audio parameter set (see [9]). 
2)
 
In audio modes with noise reduction, the microphone input signal for 0dBm0 shall be measured 
with a sine burst signal for a tone duration of 5 seconds and a pause of 2 sec. The sine signal 
appears as noise and, after approx. 12 sec, is attenuated by the noise reduction by up to 10dB.  
3)
 
Audio mode 5 and 6 are identical. With AT^SAIC, you can easily switch mode 5 to the second 
interface. Therefore, audio mode 6 is only kept for compatibility to earlier Siemens GSM products.