Audio from the eg25-GL 4g hat with a raspberry pi 4

Products & Technology Raspberry Pi
1

Hi, I am trying to get audio from the eg25-GL 4g hat with a raspberry pi 4. I followed this guide Getting Started with the Raspberry Pi 4G LTE HAT | Seeed Studio Wiki

But I am still not getting any audio when making a call via minicom. I have the gpio pins connected as well as the usb data. Any ideas? Thx

2

If your EG25-GL 4G HAT connects to the Raspberry Pi only via USB and GPIO, you’ll need to enable the correct audio path before hearing anything during a call. By default, the modem doesn’t send voice over USB. Use minicom and run AT+QDAI=4,0,0,1,0 to route audio through the USB interface, then reboot with AT+CFUN=1,1. After that, check with arecord -l or aplay -l — you should see a “Quectel USB Audio” device.

If you’re instead using the analog audio pins (MIC_P/N and SPK_P/N) on the HAT, change the setting to AT+QDAI=0,0,0,1,0. This routes voice through the hardware pins for external mic and speaker use. Remember that the Raspberry Pi’s 3.5 mm jack doesn’t carry the modem’s voice — audio must come from either USB or those analog pins.

Also make sure the USB audio driver is loaded with sudo modprobe snd_usb_audio if it’s missing. Once configured correctly, voice calls via ATD+<number>; will produce audio through your selected interface. For a related electronics project reference, check out this P-Channel MOSFET Driver Breakout

3

Hi, I appreciate the suggestions. I tried what you mentioned, but no luck on my side. I tried the usb way, but I can’t see the Quectel USB Audio as a device when I do aplay -l. Also, if I want to try the mic_p and spk_p, which pin is it on the eg25-GL 4g board? Is it one of the 40pins?

Thanks