A hearing aid is identified by storing a binary code in the hearing aid, receiving a transmitted code, reading out a subset of bits from the stored binary code, and comparing the transmitted code with the subset for identification. The reading step preferably reads the lowest order nibble, byte, or word of the binary code. In accordance with another aspect of the invention, a charger for the hearing aid, a controller for the hearing aid, and a programmer for the hearing aid store the identification codes for two way communication among the devices.