Set up over Wi-Fi#
This is the normal way to use PrismDesk. Nothing has to be configured on your router, and there is no account to create.
First time#
- Run the installer on the PC and let it finish. It adds the display driver, the firewall rules and the start-up entry itself. Windows will probably warn about the installer first — see "Windows protected your PC" for what to check before you run it.
- Install PrismDesk on the Android device from Google Play (or the APK on the Releases page).
- Make sure PrismDesk is running on the PC. If you left Start PrismDesk when I sign in to Windows, ready to accept a tablet ticked during setup, it already is — look for the tray icon. Closing the host window does not stop it; it stays in the tray.
- Open the app on the device. Hosts on the same network appear by themselves. Tap one and it connects with your saved settings.
That is the whole setup. The two only have to be on the same network — the same router, and the same subnet.
The host window checks its own side for you: the Connection tab starts with Readiness, which reads Ready when the driver, the firewall rules, the ports and the sign-in start-up entry are all in order, and names the part that is not when something is wrong. (If you unticked the start-up entry, that line stays open; devices can still connect.) See Troubleshooting.
If no host is found#
The app says "No hosts found yet", and If it doesn't show up opens a list of what to check. In the order that actually turns out to be the answer:
| Check | What it looks like |
|---|---|
| Is PrismDesk running on the PC? | No tray icon, or hosting was stopped from the host window. |
| Are both on the same network? | A guest SSID, AP isolation, or a 2.4 GHz and a 5 GHz network that the router keeps apart will all hide the PC. So will a PC on Ethernet and a tablet on a Wi-Fi network that the router treats as a separate segment. |
| Hotel or café Wi-Fi | These networks often stop devices from reaching each other. Turn on Mobile hotspot on the PC and connect the device to it; the app marks a host reached this way as Hotspot. The hotspot uses more of the PC's battery. |
| Is a VPN running? | A VPN on either end can swallow discovery. We hit this during development: with the VPN up, nothing was found; with it down, the host appeared immediately. You can still connect without discovery — see below. |
| 2.4 GHz | It works, but it drops out easily and we do not recommend it. The app says so on the same screen. |
The search keeps running while that screen is open, so a host appears as soon as it answers.
Connecting without discovery#
Discovery is a convenience, not the only route. The host window's Connection tab shows two things that work even when nothing is found:
- A QR code. In the app, tap Scan a QR code.
- A connection string (
prismdesk://…, with a Copy button next to it). In the app, open Other ways to connect (address, USB) → Enter a host directly, and paste it.
Use one of these two rather than typing a bare address. Both carry the PC's
certificate fingerprint (fp=), so the device can tell your PC from anything
else that answers on the network; the app then marks the host Verified. An
address typed by hand does not carry it: the app trusts whatever fingerprint
answers at that address the first time, and marks the host only Encrypted.
If the PC has more than one network adapter — a VPN adapter counts as one — the Connection tab lists Addresses of this host and asks which one to hand out, and the QR code changes with your choice. Pick the address on the same network as the tablet.
What the installer opened#
PrismDesk listens on six ports, and the installer adds one inbound firewall rule for each:
| Port | ||
|---|---|---|
| 45100 | UDP | Discovery — how the app finds the PC |
| 45101 | TCP | Control (TLS 1.3) |
| 45102 | TCP | Input — touch, pen, keyboard (TLS 1.3) |
| 45103 | UDP | Video, and the heartbeat that keeps the session alive (AES-256-GCM) |
| 45104 | UDP | Audio (AES-256-GCM) |
| 45105 | UDP | From the device: heartbeat replies, resend requests, and the camera (AES-256-GCM) |
Nothing has to be forwarded on the router — these are for the local network only. If a third-party firewall asks whether to allow PrismDesk, say yes; if you removed the rules, running the installer again puts them back.
More than one device#
With PrismDesk Pro, four devices can be connected to one PC at the same time, sharing a single capture and a single encoder. Four is the number that was verified — see devices.md — so four is the number we publish. The free edition connects one device at a time.
On a laptop#
Turning on USB tethering can drop the laptop's own Wi-Fi connection. If you use both, expect to pick one — see Set up over USB.
See also: Set up over USB · Troubleshooting · Known issues