A supporting device for an object comprises a support plate, a base plate, a pivot device, and a fastening device. A detecting element for detecting infrared rays passing through the optical filter plate is formed on a front surface of the infrared-detecting plate facing the optical filter plate. When activated, the scroll wheel locking device prevents further rotation of the scroll wheel in the direction that would normally be past the end of the document, but permits rotation of the scroll wheel in the opposite direction towards the other end of the document. In at least some embodiments, the current position of the device as indicated by the positioning receiver is also displayed, the current position of the device being indicated on the map display by a second icon displayed simultaneously with the first icon. A further set of frequencies in the range between 2 Hz and 32 Hz can be added. A loop-free common control channel is provided in the optical burst switching network to which all network nodes have access.