IBM 6400 Setup Manual page 28

Proprinter III XL and Epson FX Emulations
The Proprinter III XL and Epson FX emulations are industry-standard printer
emulations.
Printronix P-Series Printer Emulation
This code system was developed especially for Printronix line matrix
printers. As line matrix printers became more sophisticated, this code system
kept pace by adding codes that fully exploit line matrix printer capabilities.
Printronix P-Series XQ Variant Printer Emulation
This code system was devised for a series of Printronix printers
manufactured between 1974 and 1991, that are no longer available. It enables
the printer to emulate Printronix P300 and P600 printers.
This emulation appears as "P-Series XQ" on the operator panel.
Printronix Serial Matrix Printer Emulation
This printer emulation is very similar to the code systems used by an IBM
Graphics Printer, but incorporates several systems into one emulation. This
emulation enables a line matrix printer to print files coded for a serial matrix
printer, and is sometimes referred to as the Serial Matrix emulation.
This emulation appears as "Serial Matrix" on the operator panel.
NOTE: Serial matrix refers to the way printer characters are formed: A
1–8 6400 Line Matrix Printers Setup Guide, Cabinet and Pedestal Models
This emulation appears as "P-Series" on the operator panel.
moving printhead uses pins to form whole characters one at a time
and one after the other. The pins print dots according to
programmed matrix patterns. Data is sent to the printer through
either a serial or a parallel interface, but the printhead must receive
the data serially in order to form each character.
An IBM line matrix printer also forms characters with dots in
matrix patterns, but it feeds print data in parallel to many hammers
mounted on a rapidly oscillating shuttle. The hammers fire
simultaneously to print entire lines at a time.
IMPORTANT
IMPORTANT
IMPORTANT