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

Products & Technology Raspberry Pi
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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

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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

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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

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Audio from the EG25-GL 4G HAT with a Raspberry Pi 4 can be managed effectively by using the modem’s built-in audio interfaces. The EG25-GL module supports digital audio through USB as well as analog audio via microphone and speaker pins on the HAT. When connected to a Raspberry Pi 4, the simplest method is to use USB audio, where the modem appears as a standard USB sound card. This allows the Pi to handle voice calls using common Linux audio tools such as ALSA or PulseAudio. For better audio quality or custom hardware setups, the analog MIC and SPK pins can be wired to external microphones and speakers with proper amplification. Configuration usually involves setting the correct audio device and enabling voice support with AT commands. With correct setup, clear two-way audio for calls and VoIP applications is achievable.

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