IEEE 1284, the standard for bi-directional parallel printer bus support, defines two interface levels and specifies a physical and electrical interface.
The Level I interface is for devices that need reverse-mode capabilities but don't operate at high speeds. The Level II interface is for both bi-directional and high-speed communications.
The 1284 standard also defines connectors for use in the parallel interface. The 25-pin DB25 connector is defined as the Type "A" connector. The Telco 36, a 36-conductor, 0.085" centerline Champ connector with bale locks is defined as the Type "B" connector. The Type "C" connector is a 36-contact, 0.050" centerline mini connector with clip latches.
Others: Standard Parallel Printer Cable => Pre-IEEE 1284 Standard, consisted of 25C (25 conductors) wires, **also bi-directional. Mostly for Dot Matrix printer or Pre-1997 Laser Jet/Ink Jet/Bubble Jet printers.
Choice of Connectors
choice of any combination of Type A (DB25), Type B (Centronics 36 pin), and Type C (36 pin mini-connector) connectors, each finished with molded connector covers.
