Lexmark T620 Technical Reference - Page 344

8-46 Interfaces XON/XOFF Protocol Timing (RS-422) When you select this data flow control protocol, your printer sends an XOFF signal when it detects the following BUSY conditions: • Buffer full • Attendance error • Printer not in ready state XMT XON XOFF XON RXD Note: The printer sends an XOFF signal (DC3 control or X'13') to request that data transmission end until the buffer clears. About 640 free bytes remain in the buffer at this time. If the computer continues to send data after the printer sends an XOFF signal, data could be lost. Serial Errors Your printer places an underscore character in the link buffer when it detects an error. Some printers post a 54 Standard Serial Error or a 54 Serial Option x Error (x represents the number of the serial port) the first time they detect a transmission error (parity, overrun, or framing). The 54 Standard Serial Error or the 54 Serial Option x Error can be reset from your printer operator panel or through MarkVision Professional. Refer to your printer user documentation for more information. If repeated serial errors occur, power the printer off and then back on to restore proper serial operation. The Serial errors that do not generate such an error message are: • Serial Break • Framing error received simultaneously as a Break • Powering on an IBM-compatible personal computer connected to the printer