Cards written from the booking
Tick Key Card when you grant access. The booking is created first, then the card is written — so a failed write is only a retry, never a card in a guest's hand with no record behind it.
Works when the internet doesn't
A key card carries its own access on the plastic. The door opens whether or not the lock, the desk or the property is online.
Sits quietly in the tray
Starts with Windows, runs in the system tray, and reports the encoder it can see. The desk only opens it when something needs looking at.
Before you install
Windows 10 or 11, 64-bit
The installer bundles everything else it needs.
A Mosler USB card encoder
Supplied with your property. Plug it in before first launch so the app can find its COM port.
Blank Mifare M1 cards
Cards already programmed by another system cannot be reused — they can't be re-keyed. Blank stock, or cards this property issued before.
Your Mosler sign-in
The same account you use for the client portal. Front desk, manager, regional manager and admin roles can enrol an encoder.
Installing
Run the installer
Open the file you just downloaded and follow the prompts. It installs for the current Windows user, so no administrator password is needed.
Choose "More info" if Windows warns you
Windows SmartScreen shows a blue "Windows protected your PC" screen for installers it hasn't seen many times before. Click More info, then Run anyway. Check the SHA-256 below first if you want to be certain the file is ours.
Sign in
A small window asks for your Mosler email and password, then which site this desk belongs to. If you only have access to one site it is chosen for you.
Plug in the encoder
The app finds it automatically and shows the port it is on. From then on it starts with Windows and waits in the tray.
Verify your download
The installer is not yet code-signed, so Windows will not vouch for it by name. You can confirm the file is exactly the one we published by checking its SHA-256 fingerprint in PowerShell:
Get-FileHash -Algorithm SHA256 .\Mosler-Card-Encoder-Setup-1.0.2.exead9524e590ac263afae8186b4e80e9664347272a4fd1fda4db8525d47c846be3The Hash it prints should match this exactly. If it doesn't, delete the file and download it again.
If something isn't right
The app says the encoder isn't connected
Check the USB cable, then close any other card or serial software — Windows only lets one program hold a COM port at a time. The troubleshooting panel in the app lists every port it can see.
"This card cannot be used"
The card is already programmed by another system, and a card's keys cannot be overwritten without them. Use a blank Mifare M1 card, or one this property issued before.
"This card belongs to another guest"
The card is still live for a booking that hasn't been closed out. The portal links straight to that booking so you can clear the card there, or simply use a different card.
The card writes but the door won't open
The lock has to be told which property it belongs to before it will trust any card. That is a one-time setup we do per lock — contact support and we'll arrange it.
Sign-in is refused
Enrolling an encoder needs a front desk, manager, regional manager or admin role. Housekeeping and maintenance accounts cannot enrol one; the app tells you who to ask.
Still stuck?
Send us the diagnostics report from the app's troubleshooting panel — it captures the encoder, the port, the app version and the last error, which is usually enough for us to answer in one reply.