Headphone Jack

The Radxa ROCK 4D features an onboard 3.5mm 4-pole headphone jack that supports both audio input and output.

User Guide

Connect your headphones to the ROCK 4D's 3.5mm headphone jack using a standard audio cable, then play audio on the ROCK 4D to test the sound output.

If you don't hear any audio, try unplugging and reinserting the headphone cable or verify that the correct audio output device is selected.

Viewing Audio Devices

Use the aplay -l command to view audio playback devices (speakers) and arecord -l to view audio recording devices (microphones).

• View Playback Devices

radxa@radxa-4d$

aplay -l

Terminal output will show information similar to below. The card 1: rockchipes8388 represents the onboard ES8388 audio codec, which is typically used for both input (microphone) and output (audio playback) through the 3.5mm headphone jack.

card 0: rockchiphdmi0 [rockchip-hdmi0], device 0: rockchip-hdmi0 i2s-hifi-0 [rockchip-hdmi0 i2s-hifi-0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: rockchipes8388 [rockchip-es8388], device 0: dailink-multicodecs ES8323 HiFi-0 [dailink-multicodecs ES8323 HiFi-0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

• View Recording Devices

radxa@radxa-4d$

arecord -l

The output will be similar to the following information: The onboard ES8388 audio codec card 1: rockchipes8388 is typically used for both input (microphone) and output (audio playback) through the 3.5mm headphone jack.

radxa@radxa-4d$

card 0: rockchiphdmi0 [rockchip-hdmi0], device 0: rockchip-hdmi0 i2s-hifi-0 [rockchip-hdmi0 i2s-hifi-0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: rockchipes8388 [rockchip-es8388], device 0: dailink-multicodecs ES8323 HiFi-0 [dailink-multicodecs ES8323 HiFi-0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

Recording Audio

This feature requires headphones with a built-in microphone. Use the arecord command to record audio.

radxa@radxa-4d$

sudo arecord -Dhw:1,0 -d 20 -f cd -r 44100 -c 2 -t wav /tmp/tmp.wav

• -Dhw:1,0: Uses device 0 of card 1: rockchipes8388
• -d 20: Records for 20 seconds
• -f cd: Uses CD audio format (16-bit little-endian, 44100Hz, stereo)
• -r 44100: Uses 44.1kHz sample rate
• -c 2: Records in stereo (2 channels)
• -t wav: Saves in WAV format
• /tmp/tmp.wav: Output file path

Playing Audio

Use the aplay command to play audio.

radxa@radxa-4d$

sudo aplay -Dhw:1,0 /tmp/tmp.wav

• -Dhw:1,0: Uses device 0 of card 1: rockchipes8388
• /tmp/tmp.wav: Input file path

Interface Specifications

tip

For detailed interface specifications, please refer to the Hardware Design: Schematics in the download section.

Left Channel Pin#	Left Channel Name	Right Channel Pin#	Right Channel Name
1	SPK_CTL_H	1	SPK_CTL_H
2	GND	2	GND
3	GND	3	GND
4	AUD_LINEOUT_L	4	AUD_LINEOUT_R
5	AUD_SPK1P	5	AUD_SPK2P
6	VCC_SPK_AMP	6	VCC_SPK_AMP
7	GND	7	GND
8	AUD_SPK1N	8	AUD_SPK2N