The invention relates to an apparatus for providing information to a printer controller in order to identify the type of printer cartridge installed in a thermal ink jet printer. The apparatus includes a printer cable containing a set of electrically-conductive wires connected to contacts in a printer cable connector. The contacts of the printer cable connector make physical connection to an identification circuit on the printer cartridge. The identification circuit includes an electrical conductor which is at an electrical reference potential. When none, or one or more contacts on the cable connector are in electrical contact with the electrical conductor of the identification circuit, a signal corresponding to the identification of the printer cartridge is produced which is used by the printer controller to determine the type of printer cartridge installed in the printer. Selective contact between the connector contacts and the identification circuit, so as to produce an electrical code, may be obtained using a label having apertures, contact pads, electrical traces, or a combination thereof. Accordingly, various cartridge identification codes can be produced using various methods which allow encoding of the information on a cartridge during or after the manufacture of the cartridge body is substantially complete.