Devices that connect via a WLAN and Internet to communication network, e.g. a Public Switched telecommunication network (PSTN) can call e.g. an emergency centre. The method proposed, defines enables the device that initiates a call setup via a WLAN to provide the emergency centre with geographical location information by retrieving this information locally by e.g. a GPS module. The operator of the phone of the subscriber maintains a database wherein the identity of the Subscriber Identity Module (SIM) is recorded. The subscriber is enabled to add devices that generally have no SIMs (non-SIM devices), such as tablets to the database. In determining whether a WLAN based call setup to the emergency centre is allowed, it is checked with the database whether a record for the non-SIM device is present, and valid.