These new uses caused manufacturers to look at new ways to make the Centronics parallel interface better. In 1991, Lexmark, IBM, Texas instruments, and others met to discuss a standard that would offer more speed and bi-directional communication. The IEEE 1284 standard was approved for release in March, 1994. Compatibility mode is the original Centronics parallel interface and intended for use with dot matrix printers and older laser printers. The compatibility mode can be combined with the nibble mode for bi-directional data transfer.
Nibble mode allows data transfer back to the computer.
This mode is best used with printers. Byte mode uses software drivers to disable the drivers that control the data lines in order for data to be sent from the printer to the computer. The data is sent at the same speed as when data is sent from the computer to the printer. One byte of data is transferred instead of the two data cycles required by the nibble mode. Data transfer occurs at two to four megabytes per second.