To use the service you can send from your mobile phone SMS text 0887 free number 111. In return you will receive a message, which will set your room phone.
In addition, the service is "Know your room" available via voice call. You can call the toll free numberat 0887, and the answering machine will inform you forgotten room. Call number 0887 possible only if your location on your home network.
If for some reason you can't write SMS and are in roaming, a simple way to find your number will call your friend. His mobile phone will recognize your number when you call.