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Help · iPhone & iPad

Pairing a Mac

Before you start

  • AtControl Mobile installed on the iPhone or iPad — during the beta, from the iPhone & iPad beta on TestFlight.
  • AtControl running on the Mac.
  • The same iCloud account on both devices. This is not optional: the channel between them is the private database of that account. A second macOS user account on the same machine is, to AtControl, a separate Mac with its own pairing.
  • The phone app needs an iCloud account at all: without one it shows a full-screen notice (“Sign in to iCloud”) instead of the app, and says so differently when the account is restricted or still being set up.

On the Mac

  1. Settings ▸ iPhone ▸ turn on iPhone sync (or take the “Watch it from my phone” option in the setup assistant, which does this for you).
  2. Press Pair an iPhone…. A QR code appears with a ten-minute countdown, five attempts, and a Copy Pairing Link button for a device that cannot scan.

On the phone

  1. Open AtControl. Before anything is paired the whole app is the Pair a Mac screen: the Macs on your account that have a pairing window open or are already paired with another device, each with “Ready to pair” or, greyed, “Start pairing on the Mac”. Pull to refresh or Search Again.
  2. Tap the Mac. The Pair This Mac sheet offers Scan QR Code — or, under Can’t scan?, paste the same link (Paste from Clipboard · Pair with Link). Both carry the same 256-bit secret; typing is not a weaker path.
  3. “Waiting for the Mac to confirm…” — a second or two. The Mac countersigns, the sheet dismisses itself, and you land on the Mac’s detail screen.

Errors you may see: The pairing window on the Mac is closed or expired (start again on the Mac), That is not an AtControl pairing code, That pairing code belongs to a different Mac.

What just happened

Each device holds its own identity key. The QR secret authenticated an exchange of those keys, and the Mac countersigned the phone’s acceptance; both sides now trust one specific key on the other, bound to a random pairing id. From here every command the phone sends is signed, and every status the Mac publishes is signed. The trust model has the details.

The journal on the Mac records “iPhone paired”. The Mac’s Settings ▸ iPhone lists the device.

A second Mac, a second phone

  • Another Mac: on the phone, Settings ▸ Macs ▸ Pair another Mac…. With two or more Macs the app opens on My Macs, one card each. Two accounts on one machine share a hardware name; the app adds the account name, and you can set a nickname.
  • Another phone: repeat the pairing on the Mac; each phone completes its own handshake and is listed separately.

Unpairing

  • From the Mac: Settings ▸ iPhone ▸ remove the device. Its commands are refused immediately, and what that phone left in iCloud is deleted.
  • From the phone: the Mac’s detail screen ▸ Unpair This Mac (Forget This Mac on an iPad). It asks in a system alert. This removes the pairing, this Mac’s keys, its local activity data and its notifications from the device.
  • Either way the phone keeps nothing about that Mac, and a phone left with no Mac paired erases everything it held. When the last phone goes, the Mac deletes its data from iCloud too; turning iPhone sync off on the Mac unpairs every phone the same way.
  • Each side also checks rather than only listens: at start and on refresh it asks iCloud whether its pairing record still exists, so a deletion made while the app was off is noticed.
  • Unpairing does not erase the Mac’s own journal. Erase All Data in Settings ▸ Advanced does — see the trust model.