A smart room is only as useful as the systems it talks to. KNX room control reaches its full value when it is wired into the hotel's PMS and GRMS - the platforms that already run check-in, housekeeping and the front-desk dashboard. This deep dive explains the event flow, the interfaces, and what keeps working when the network does not.
What PMS and GRMS each own
The PMS (Property Management System) owns the commercial truth of the hotel: reservations, check-in and check-out, room assignment and billing. The GRMS (Guest Room Management System) is the translation layer that turns those business events into room behaviour and reports room status back. KNX sits at the bottom, executing scene and load control inside each room.
The event flow: check-in to check-out
- Check-in: PMS sends the room-occupied event; GRMS applies the welcome scene (comfort temperature, lighting ready).
- Occupied: KNX runs comfort settings and reports door, power and fault status.
- Check-out: PMS releases the room; GRMS switches it to the vacant energy profile and flags it for housekeeping.
Service requests: DND, MUR and help
Guest and housekeeping actions at the panel - Do-Not-Disturb, Make-Up-Room, and help requests - are picked up by KNX, passed through GRMS and shown on the front-desk dashboard. The desk sees status without a phone call, and housekeeping routing becomes automatic.
A unified event bus
Keeping every room event on one bus means the property gets a single, auditable view: who is in which room, which rooms need service, and which rooms are misbehaving electrically. That view is what lets a small engineering team manage a large property.
The interface: TCP/IP and the room-status protocol
KNX does not speak PMS natively. An IP router bridges the room bus to TCP/IP, and the GRMS exposes open room-status interfaces that map to mainstream PMS platforms through a standard room-state messaging model. This keeps the field bus simple while the integration lives in software.
What still works when the network drops
KNX is a local closed loop. If the building network or internet drops, in-room control keeps working - lights, climate and scenes still respond at the panel - and only the upstream reporting and PMS sync pause until connectivity returns.
Frequently asked questions
- Does it support Opera and Protel?
- Yes. HOTEKEY's GRMS exposes open room-status interfaces over TCP/IP that map to mainstream PMS platforms, including Opera and Protel, through standard room-state messaging.
- Does the room still work if the internet is down?
- Yes. The KNX bus is a local closed loop, so in-room control keeps working during an outage; only the upstream reporting and PMS sync pause until connectivity returns.