[. . . ] [. . . ] Before using the serial interface, you must remove the cable from the parallel interface port!When the Serial Board is installed, the following new items appear in the printer menu: Sets which line your system monitors for a busy signal if the Ready/Busy protocol is engaged. Sets the way your system handles the DSR signal when the Ready/ Busy protocol is engaged. Sets the length of the busy signal when the Ready/Busy protocol is engaged. [. . . ] [. . . ]