Revision Standard - Inactive-Reserved. A signaling method for asynchronous, fully interlocked, bidirectional parallel communi-cations between hosts and printers or other peripherals is defined. A functional subset of thesignaling method may be implemented on personal computers (PCs) or equivalent parallel porthardware with new software. New electrical interfaces, cabling, and interface hardware thatprovides improved performance while retaining backward compatibility with this subset is detailed.