Abstract: A bar code scanner having means for reading bar code data and for processing the data includes means for supplying the processed data to a computer having an input/output (I/O) port designed for the connection thereto of an external keyboard. The scanner includes "communication" means for enabling the scanner either to be "wedged" between an external keyboard and the I/O port or to be directly connected to the I/O port. The scanner's "communication" means includes means for sensing whether an external keyboard is connected to the computer and includes means responsive to sensing the absence of an external keyboard connection for producing signals similar to those produced by an external keyboard and for supplying these signals to the computer in order to establish and maintain communication between the scanner and the computer. The bar code scanner may also include means for responding to various computer commands and/or keyboard commands.