A demonstration system for a peripheral such as a printer connects an external, non-volatile memory to the printer in place of the host computer. One such peripheral uses a peripheral cable containing a controller or formatter that includes a computer interface for communications with the host computer and an interface for memory accesses. The peripheral cable connects to the computer interface for communications with the host computer. The demonstration system employs a controller or formatter of the same type as used in the peripheral cable and connects the interface for reading from the external memory. The controller can load both demonstration code and demonstration data from the external memory and direct the peripheral to perform a demonstration.