Epson LQ-2550 User Manual - Page 246

CHASSIS GND 32 - ERROR 33 - GND 34 - NC 35 - - 36 - SLCT IN s LOW, the printer controller is reset to its power-up state and the print buffer is cleared. This level is usually HIGH; its pulse width must be more than 50 microseconds at the receiving terminal. OUT zis level becomes LOW when the printer 1) in paper-out state 2) off line 3) in error state. - Same as for Pins 19 - 30. - Not used. OUT Pulled up to 5V through 3.3K ohm resistance. lN The DClIDC3 code is valid only when this signal is "HIGH". he same effect can be achieved with&YelecType.) l The column heading "Direction" refers to the direction of signal flow as viewed from the printer. 0 "Return" denotes the twisted-pair return, to be connected at signal ground level. For the interface wiring, be sure to use a twisted-pair cable for each signal and to complete the connection on the return side. These cables should be shielded and connected to the chassis of the host computer and the printer. A-10 Technical Specifications