User guide

Install on a Mac

1. Download AirLink for Mac.
2. Unzip AirLink.zip and drag AirLink into Applications.
3. Open it. AirLink checks for new versions, verifies they are signed by its developer, and installs them when you quit; AirLink › Check for Updates… asks on demand.

It needs macOS 14 or later, on Apple silicon or Intel, and is signed with a Developer ID and notarized by Apple.

Before you start

AirLink asks for these permissions, each the first time it is needed:

On the Mac, the Bluetooth permission is tied to the app's code signature. A build signed with a stable identity is asked once.

Both people need AirLink open. Neither device needs Wi-Fi, a SIM or an internet connection.

Go on the air

1. Open Chats.
2. Under Join the mesh, type the name other people will see.
3. Press Go on the air.

From then on AirLink joins the mesh every time it starts. Your number, eight characters such as A3F9-K2P1, appears under Your number in Calls. It is derived from keys generated on this device the first time you go on the air, and it stays the same across launches and when you change your name.

Find people

Nearby AirLink devices appear in Chats and Calls on their own within moments of coming into range, under the name they chose.

To add someone by number:

1. Open Calls and add a new contact.
2. Type their number, with or without the hyphen, and a name for them.
3. Press Save.

If they are not in range yet, the name waits and attaches itself when a device with that number appears. Typing is forgiving: O is read as zero and I or L as one.

To rename a contact, choose Rename…. The name you give them is stored on your device only; they keep their own.

Send a message

1. Open Chats and choose a person.
2. Type up to 3,500 characters and send.

A message shows as sending until the recipient's device returns a sealed receipt, then as delivered. If the recipient is not in range, your device keeps the message and offers it again to every device that connects, for as long as AirLink stays open.

Make a call

1. Open Calls and choose a contact, or use the keypad to dial a number.
2. The other device rings. On iPhone and iPad this is the system call screen, including on the lock screen. On the Mac, a notification banner appears when AirLink is not in front.
3. When they answer, audio starts at once over the mesh and moves to a direct Wi-Fi path when one works. The call screen shows which road the audio is on.

During a call you can Mute, and on iPhone and iPad switch the Speaker on. Press End to hang up.

A call rings for up to sixty seconds. A device that comes into range or opens AirLink during that minute still rings. One call at a time: a second caller hears a decline.

Calls are listed in Recents and in the conversation with that person. On iPhone and iPad they are not written to the phone's own call history.

Remove a conversation or a device

• Delete Conversation removes the messages and call history with that person, on this device only.
• Remove Device… removes the person, their name and their history from this device. If their device is still nearby and announces itself again, it comes back as a new contact.

Find a nearby device

AirLink's finder helps you locate a Bluetooth device by walking towards it.

1. Nearby lists every Bluetooth device in range, strongest first. Filter by phones and watches, named devices or favourites.
2. Choose one to Hunt. The screen shows a large live reading, a distance range and whether you are getting warmer. If the device accepts connections, AirLink reads its signal directly several times a second.
3. Turn on the proximity sound, and on iPhone the haptics, to search without looking at the screen.

On an iPhone with ultra-wideband, Precision in Hunt shows a direction arrow and a distance to another AirLink iPhone that also has the radio. The two phones exchange the session token over the mesh.

On the Mac, Paired lists the Bluetooth devices the Mac is paired with. iOS gives apps no access to classic Bluetooth, so the iPhone app sees Bluetooth LE only.

Calibration

Distance comes from a reference: the signal strength at one metre, −59 dBm by default. To calibrate, hunt your device, hold it one metre away in clear air, and choose Calibrate from that device in Settings.

Mask identifiers

Mask identifiers hides Bluetooth addresses and other people's device names on screen, for recordings. Names you typed stay visible.

Activity

Activity lists everything the engine has done, in order: links coming up and down, people met, messages sent and delivered, calls and their audio. It is the first place to look when something does not work.

Lab mode

Settings contains a Lab mode switch used for measurement sessions. It is off by default and switches itself off after three hours. It is not needed for normal use. See Security and privacy for what it records.