Abstract: A color capable electrophotographic printer remains operable for monochrome printing when one or more developing unit are unavailable for use. Instead of reverting to an error state when a developing unit is missing or unavailable, the laser printer remains operable to print monochrome images or single "spot color" images using a single color and monochrome developing unit.

Abstract: A color capable electrophotographic printer remains operable for monochrome printing when one or more toner cartridges are unavailable for use. Instead of reverting to an error state when a toner cartridge is missing or unavailable, the laser printer remains operable to print monochrome images or single "spot color" images using a single color and monochrome toner.

Abstract: A simplified installation method is provided in this improved insulation seal for inspection holes. The sealing assembly consists of a compressible elastomeric flanged hollow sleeve which is first inserted into the inspection hole. A rigid metal cup-shaped plug then inserted into the sleeve forms tight weatherproof seals in downward and outward directions against the insulation jacket. No special installing tools are needed and the seal is adaptable to severely corrugated, or other non-flat, insulation jackets. Primary exposure of the metal plug protects the assembly against sand blasting and other external wear. The seal is easily removed for reuse upon later inspections.

Abstract: The invention is an improved remote control signal device that is portable. The remote control signal device is provided with an alarm, a remote control means connected to the alarm by electrical conductors, and a power source for the system. A novel connection is made in the power plug to permit the remote control means to activate the alarm at will.