Repair, maintenance, and replacing of automatic identification, data collection and data storage, and supply chain apparatus, including data printing and bar code reading devices, namely, electronic label and tag printers, bar code readers, scanners, and imagers, hand-held light pens and wands, signal multiplexers for coupling a plurality of bar code readers to a computer, batteries, battery chargers and dischargers, interconnect cables, signal interface modules and units, power supplied laser scanners, contact and non-contact scanners, concentrators and protocol converters for providing bi-directional data communications between a plurality of bar code readers and printers and a host computer and integrated terminal devices having keyboards for providing data to a central data base, such terminals also processing and scanning indicia containing bar codes and other symbology, electronic controllers for machining and assembly of machines, hand-held data collection computer terminals, portable programmable bar code readers, and hand-held scanners with a keypad and display, radio frequency identification interrogators, wireless scanners, terminals, and interrogators, all the foregoing data collection, identification, and data storage apparatus for use in WAN and LAN applications