A variety of PC card interfaces to interface from many different types of input devices to Personal Digital Assistants or palmtop computers through PCMCIA slots. The disclosed interfaces can receive data in undecoded format from laser based, wand based or CCD based barcode scanning engines, decode the data to alphanumeric characters and pass the decoded data to the PDA via the PCMCIA 68 pin bus. Other PC card based interfaces are also disclosed which can accept input data in the form of ASCII or EBCDIC characters from virtually any type of input device which a standard serial or parallel output or custom output bus and input that data to the PDA through the PCMCIA bus. Some embodiments use programmed general purpose microprocessors to decode undecoded barcode scan data on the PC card. Other embodiments use custom-programmed, commercially available barcode decoding chips to decode incoming undecoded barcode scan data. Some embodiments of PC card interfaces sample undecoded barcode scan signals and pass the samples to the host through the PCMCIA bus for decoding by a suitably programmed host computer.