G06K 7/10465

Methods or arrangements for sensing record carriers, {e.g. for reading patterns} by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation {sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves the interrogation device being adapted for miscellaneous applications the interrogation device being capable of self-diagnosis, e.g. in addition to or as part of the actual interrogation process }