jabra-sidetone-linux

Sidetone and busylight for Jabra headsets on Linux.

Jabra's own configuration tool, Jabra Direct, is Windows and macOS only. On Linux the sidetone setting appears to do nothing, and the busylight never lights. This is a small pair of shell scripts that fixes both.

The problem

Sidetone on a Jabra headset is a call-mode feature: the headset only mixes your own voice back into the earcups when it believes a call is in progress. Crucially, call state travels over HID, not over audio. They are two independent channels:

Channel	What it does	On Linux
USB audio	dongle switches the Bluetooth link into bidirectional call mode	happens automatically when an app opens the mic
HID telephony	tells the headset "a call is in progress"	nothing sends this

So Linux gets all of the cost of call mode and none of the benefit. The moment any application opens the microphone, playback drops to speech bandwidth and sounds thin — but the headset itself is never told a call is happening, so sidetone never engages and the busylight stays dark.

Enabling sidetone in Jabra Sound+ or Jabra Direct does not help. The setting is already stored in the headset's firmware, waiting for a signal that never arrives.

The fix

Jabra devices expose a standard HID Telephony output report:

05 0b  Usage Page (Telephony)      09 05  Usage (Headset)
85 02    Report ID 2
05 08    Usage Page (LED)
09 17      Off-Hook   <- bit 0     "there is a call in progress"
09 1e      Speaker    <- bit 1
09 09      Mute       <- bit 2
09 18      Ring       <- bit 3
09 20      Hold       <- bit 4
09 21      Microphone <- bit 5
09 2a      On-Line    <- bit 6
91 22    Output (Data,Var,Abs)

Writing 02 01 00 to the device's hidraw node sets the Off-Hook bit — exactly what Jabra Direct does on Windows when a softphone starts a call. The headset lights its busylight and turns on sidetone.

jabra-call sends those reports. jabra-call-daemon watches PipeWire/PulseAudio and sends them automatically, holding the headset off-hook for as long as any application has the microphone open.

Install

git clone https://github.com/Sm4rtens/jabra-sidetone-linux
cd jabra-sidetone-linux
./install.sh

Requires pactl (PipeWire or PulseAudio), jq, and a systemd user session. The installer needs sudo once, for the udev rule.

Verify:

jabra-call status     # prints the /dev/hidrawN it found
jabra-call start      # busylight turns red, sidetone comes on
jabra-call stop

If jabra-call reports the device is not writable, the udev rule has not been applied yet. uaccess is granted when the device is added, so replug the headset or dongle, or run:

sudo udevadm trigger --action=add --subsystem-match=hidraw

Usage

Once the service is running, nothing else is required — join a call and the headset goes off-hook on its own.

jabra-call start | stop | toggle | mute | unmute | status

toggle is handy on a hotkey. It pins call state against the daemon until the set of applications holding the mic next changes, so an override applies to the call you meant it for and no longer. Outside a call it doubles as a do-not-disturb light.

The daemon also mirrors mic mute to the headset's mute LED, and hangs up on SIGTERM, so stopping the service or logging out never leaves the headset stuck off-hook with a red light.

Known and expected: thin audio during calls

While a call is active, music and system audio sound thin — less bass, more treble. This is not a bug in this tool and it cannot be fixed here. A bidirectional Bluetooth link is speech-bandwidth by nature; the same thing happens on Windows during a Teams call. Mic input and hi-fi playback are mutually exclusive on this hardware.

It is the reason the daemon signals call state only while an application actually holds the microphone, rather than keeping the headset off-hook permanently. You pay the cost during calls, when you were going to pay it anyway, and never while you are just listening to music.

This only bites if you use the headset's own microphone. If you take calls on a separate mic - a webcam or a desk mic - nothing ever asks the headset for bidirectional audio, so it stays in full-bandwidth playback the whole time and you will never see this at all. That is a perfectly reasonable setup: you give up the noise-cancelling boom, and you keep hi-fi playback during calls. Worth knowing before you conclude something is broken.

The degradation is not visible from the host. USB playback stays 48 kHz stereo S16_LE in both states - /proc/asound/card*/stream0 reports the same format throughout - so it happens downstream of the dongle, on the Bluetooth link itself. Confirmed by opening the mic with no HID call state sent at all: playback thins out on mic activity alone, independently of anything this tool does.

Tested on

Developed against a Jabra Evolve2 65 paired through a Jabra Link 380 (USB 0b0e:24c8) on Arch Linux with PipeWire.

The HID Telephony report used here is part of the USB HID specification rather than anything Jabra-specific, so other Jabra headsets and dongles that expose a Telephony collection should work unchanged. Device matching is by vendor id 0b0e plus the presence of that collection, not by product. Reports of other models working or failing are welcome.

Configuration

Environment variables, if the defaults do not fit:

Variable	Default	Purpose
JABRA_DEVICE_MATCH	Jabra	substring matched against PipeWire source names
JABRA_CALL	jabra-call	path to the jabra-call binary
JABRA_DEBOUNCE	0.4	seconds to settle before reacting to an audio event

Prior art

• HeadsetControl — sidetone for gaming headsets. Supports Logitech, SteelSeries, Corsair, HyperX and others; no Jabra support.
• jLink — Jabra device management for Linux (discovery, pairing, battery). Does not implement sidetone or call state.

License

MIT