Specifications

CINTERION

BGS12 Hardware Interface Description

Contents

49 of 109

Page

BGS12 HID_V00.915

Confidential / Released

2019

3.11 Analog Audio Interface

BGS12 has an analog audio interface with a balanced analog microphone input and a ba-

lanced analog earpiece output. A supply voltage is provided at dedicated pad.

BGS12 offers four audio modes which can be selected with the AT^SNFS command. The

electrical characteristics of the voice band part vary with the audio mode. For example,

sending and receiving amplification, side tone paths, noise suppression etc. depend on the

selected mode and can be altered with AT commands.

Please refer to Section 5.6 for specifications of the audio interface and an overview of the audio

parameters. Detailed instructions on using AT commands are presented in [1]. Table 30

summarizes the characteristics of the various audio modes and shows what parameters are

supported in each mode.

When shipped from factory, all audio parameters of BGS12 are set to default audio mode.

3.11.1 Microphone Inputs and Supply

The differential microphone inputs MICP and MICN present an impedance of 2kOhm and

must be decoupled by capacitors (typical 100nF). A regulated power supply for electret micro-

phones is available at VMIC. The voltage at VMIC is rated at 1.8V and available while audio is

active (e.g., during a call). It can also be controlled by AT^SNFM. It is recommended to use an

additional RC-filter if a high microphone gain is necessary.

The following figures show possible microphone and line connections.

Figure 21: Single ended microphone connection