GPSLarpHelp

Cable or Wi-Fi — which should I use?

You want to know whether GPSLarp needs the iPhone plugged in, or whether it can find the phone across the room.

A cable once, then either. The very first pairing has to happen over a cable — iOS gives you no other way to do it — and after that the phone can be found over Wi-Fi as long as both devices are on the same network. When something is not working, go back to the cable, because it takes the entire network out of the question in one move.

01The first time, it has to be the cable

This is not a GPSLarp requirement and there is no setting that changes it. iOS creates the trust relationship between a phone and a computer over a cable, with the phone unlocked, confirmed by typing the phone's passcode. There is no version of that handshake that happens over a network.

Practically, that means one cable, once, per computer. If you have never connected this particular Mac to this particular iPhone, no amount of Wi-Fi will introduce them — the phone will sit there and answer nothing, which looks exactly like a phone that is not on the network. The prompt itself, and what to do when it does not appear, are on My iPhone won't trust this computer.

02After that, Wi-Fi works

The app says so itself, in the sentence it shows beside an empty device list: "Connect it with a cable and unlock it once — tap Trust if asked. After that first pairing it can also be found over Wi-Fi, as long as both devices are on the same network."

Both halves of that last clause carry weight. Same network is a stricter condition than it sounds like, and it is where most Wi-Fi disappointments live — see why Wi-Fi quietly fails below.

03The cable has to carry data

Many cables sold for charging do not carry data at all. They are not faulty and nothing about them looks different: the phone charges, the battery icon does what it should, and the Mac never sees a device. It is the single most common cause of a phone that is plugged in and invisible.

The test takes five seconds — swap the cable for one you know moves data, or use the one that came in the phone's box — and people reliably leave it until last because plugging something in feels like it has already been ruled out. Do it first. The same goes for trying a different port on the Mac.

04Why Wi-Fi quietly fails

Every item in this list produces the identical symptom: the connection is up, the app looks, and there is nothing there. None of them reports itself, and none of them can be worked around from inside GPSLarp, because the block is in the network rather than in the app.

• A guest network. Guest networks exist specifically to stop devices on them from seeing each other.
• Client isolation on the router, which is the same idea under a different name and is on by default on a fair number of consumer routers and most public networks.
• Two different networks with similar names — a 2.4 GHz and a 5 GHz band published as separate names, or a mesh extender with its own. Compare the names on both devices letter for letter rather than by eye.
• A VPN on either device. A VPN on the Mac routes it away from its own local network; a VPN on the phone does the same in the other direction. Nothing announces this.
• The Mac asleep, or asleep enough to have dropped its network. Nothing found is the correct answer at that point.

05Which to reach for when something is wrong

The cable, every time — and the reason is worth being precise about, because it is a reason about diagnosis rather than about performance.

Wi-Fi adds five or six ways to fail that have nothing to do with the phone, the Mac, or GPSLarp, and none of them announces itself. A cable removes all of them at once. So when you are trying to work out where a problem is, plugging the phone in is not a fix — it is the move that shrinks the number of possible answers, which is what you want first.

One thing that is true either way: a locked phone is not reliably reachable. Unlock it before deciding that the transport is the problem.