07-04-2022, 05:53 AM
You could try investigating the modem's echo cancellation settings. The AT command manual includes AT+QEEC
Set Echo Cancellation Parameters, but provides no detail about what any of the parameters do. It may be purely a passthrough to some native Qualcomm settings. The call audio routing on the pinephone bypasses the alsa and pulseaudio mixers so we don't get to use software echo cancellation. I haven't checked the routing for the PPP but I suspect it's a similar situation.
Set Echo Cancellation Parameters, but provides no detail about what any of the parameters do. It may be purely a passthrough to some native Qualcomm settings. The call audio routing on the pinephone bypasses the alsa and pulseaudio mixers so we don't get to use software echo cancellation. I haven't checked the routing for the PPP but I suspect it's a similar situation.