ABSTRACT
Until about 1991, the features offered by the standard parallel port (in terms of speed, data buffering, etc.) didn’t progress as quickly as the performance characteristics of host computers. In 1991 various printer manufacturers formed a group called the Network Printing Alliance (NPA). This organization sought to develop a standard for the control of printers across a network. As part of their work, NPA decided to look at the parallel port and to define new protocols that would increase performance and provide bidirectional communication while retaining backward compatibility with existing parallel ports.
