Specifications

M80 Hardware Design
M80_HD_V1.0 - 53 -
3.10. Audio interfaces
The module provides two analogy input channels and three analogy output channels.
Table 11: Pin definition of Audio interface
AIN1 and AIN2 can be used for input of microphone and line. An electret microphone is usually
used. AIN1 and AIN2 are both differential input channels.
AOUT1 is used for output of the receiver and speaker. This channel is typically used for a receiver
built into a handset. AOUT1 channel is a differential channel. It only supports voice path. If it is
used as a speaker, an amplifier should be employed.
AOUT2 is used for output of earphone and speaker. This channel is typically used with earphone.
AOUT2 is a single-ended channel. SPK2P and AGND can establish a pseudo differential mode. If
customer needs to play Melody or Midi ring tone for incoming call, AOUT2 Channel should
always be used. If it is used as a speaker, an amplifier should be employed also.
AOUT3 is used for loud speaker output as it embedded an amplifier of class AB whose maximum
drive power is 800mW. AOUT3 is a differential channel. Immediately Playing Melody or Midi
ring tone for incoming call is available in AOUT3.
These three audio channels can be swapped by “AT+QAUDCH” command. For more details,
please refer to document [1].
Use AT command “AT+QAUDCH” to select audio channel:
 0--AIN1/AOUT1, the default value is 0.
 1--AIN2/AOUT2
 2--AIN2/AOUT3
Interface
Name
Pin
Function
AIN1/AOUT1
MIC1P
9
Channel one of Microphone positive input
MIC1N
10
Channel one of Microphone negative input
SPK1P
12
Channel one of Audio positive output
SPK1N
11
Channel one of Audio negative output
AIN2/AOUT2
MIC2P
7
Channel two of Microphone positive input
MIC2N
8
Channel two of Microphone negative input
SPK2P
5
Channel two of Audio positive output
AGND
6
Cooperate with SPK2P
AIN2/AOUT3
LOUDSPKP
14
Channel three of Audio positive output
LOUDSPKN
13
Channel three of Audio negative output
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