Author Topic: AiThinker A6 GSM modem. Sound problems  (Read 1558 times)

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Offline IvanumTopic starter

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AiThinker A6 GSM modem. Sound problems
« on: June 16, 2018, 02:35:14 pm »
Hello guys! I apologize in advance for my English, but local fellas can't help me, so i asking here.

Recently i bought an AiThinker A6 GSM modem for my rotary dial phone upgrade project. Unlike most users of this module, i whant to use it for voice calls (most people use it for GPRS transmisions. In the most part, thats why i cant find any interesting info for my question).
Anyway, when i hooked up a headset i found a problem: my phonecall opponent hear me pretty clear and loud (not best sound quality, but exeptable), but his voice in my ear sounds wavy or intermittently. But, if opponent talks loud enouht (or blow in his mic), wavy effect in my ear disapear for a while (10 seconds, or something) or until opponent start to talking normally again. I thought that is a gain problem inside a modem. In AT commands (http://alselectro.com/files/A6-AT-Commands.pdf) for this module i found a gain control commands AT+VGR for speaker and AT+VGT for mic, but ajusting them just make all sound with wavy effect louder or quieter.
Also, i found a way for switching between headset out and loudspeaker out on modem (AT+SNFS=0 or AT+SNFS=1), but wavy effect was in a both ways.
Then i thought that effect appear, becouse of weak GSM signal, but there is a AT command AT+CSQ, that shows that signal is a -59db, that is very good.
Some guy online shows, how he starts up this modem from scratch (his scheme in attachments)/ He used pretty complex connection of mic and speaker. I have a module (on a photo), but i can't find a scheme of it, so i dont know, how microphone and speakers outs are made on it.

So can you help me with this? may be there is a command, that switches off some gain function, or maybe i can elliminate it some how? Or this is not worth any work, and i must buy another one?
« Last Edit: June 16, 2018, 02:56:58 pm by Ivanum »
 


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