SIM800C plays music until incoming call answered

Hi all,

I’ve summed audio output of SIM800C and FSK caller-id generator output to give line circuit of FCT.

When incoming call is received SIM800C gives music until call answered (ATA command) and this cause caller-id signal not to be detected by telephone. If I disconnect music by hardware, caller-id message is well received.

Could someone help how to prevent SIM800C playing music while incoming ring.

If not too much, I’ve another issue: Which AT commands adjust inbound and outbound voice levels during conversation?

Thank you in anticipation.

I have used the AT+CMIC=0,15 command for MIC volume setting to maximum level and CLVL command for speaker volume setting.
Not sure about the FSK FCT part. Didnt understand the question clearly. Please elaborate.

I can adjust inbound/outbound voice levels with AT+CMIC & AT+CLVL commands, thanks.

I solved ringing tone problem with “AT+CALM=1” command.

To elaborate my problem; I have an analogue summing circuit which combines audio output of SIM800C and FSK caller-id generator DAC. Since I didn’t put switching component, ringing tone generated by SIM800C was being added to FSK signal. Now it is solved.


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Glad to hear that :slight_smile: