A mobile communications apparatus comprising: a data reader for reading a machine readable marker at a facility, wherein the facility comprises a plurality of specified locations and each location comprises a corresponding machine readable marker identifying the each location; a wide area communication interface, for communication with a first server over a wide area network; and a controller, wherein the controller is configured to: obtain: (i) location data identifying a first location of the plurality of specified locations, and (ii) facility data via the data reader from one of the machine readable markers; send a first registration message to the first server, the first registration message comprising: the location data; and the facility data, wherein the facility data identifies the facility; receive an association message comprising a data association selected based on the facility data wherein the data association provides a relation between a plurality of data items and a corresponding plurality of reference values; and send, to the first server, a selection message identifying selected data items of the data association to enable the first server to identify a second device associated with the facility based on the facility data and to send, to the second device, a verification message identifying: the reference values associated with the selected data items; and, the first location; to enable verified communication between the mobile communications apparatus at the first location and the second device based on the verification message. a data reader for reading a machine readable marker at a facility, wherein the facility comprises a plurality of specified locations and each location comprises a corresponding machine readable marker identifying the each location; a wide area communication interface, for communication with a first server over a wide area network; and a controller, wherein the controller is configured to: obtain: (i) location data identifying a first location of the plurality of specified locations, and (ii) facility data via the data reader from one of the machine readable markers; send a first registration message to the first server, the first registration message comprising: the location data; and the facility data, wherein the facility data identifies the facility; receive an association message comprising a data association selected based on the facility data wherein the data association provides a relation between a plurality of data items and a corresponding plurality of reference values; and send, to the first server, a selection message identifying selected data items of the data association to enable the first server to identify a second device associated with the facility based on the facility data and to send, to the second device, a verification message identifying: the reference values associated with the selected data items; and, the first location; to enable verified communication between the mobile communications apparatus at the first location and the second device based on the verification message. obtain: (i) location data identifying a first location of the plurality of specified locations, and (ii) facility data via the data reader from one of the machine readable markers; send a first registration message to the first server, the first registration message comprising: the location data; and the facility data, wherein the facility data identifies the facility; the location data; and the facility data, wherein the facility data identifies the facility; receive an association message comprising a data association selected based on the facility data wherein the data association provides a relation between a plurality of data items and a corresponding plurality of reference values; and send, to the first server, a selection message identifying selected data items of the data association to enable the first server to identify a second device associated with the facility based on the facility data and to send, to the second device, a verification message identifying: the reference values associated with the selected data items; and, the first location; the reference values associated with the selected data items; and, the first location; to enable verified communication between the mobile communications apparatus at the first location and the second device based on the verification message.