LP 2 (26-1154A) Control Codes Faxback Doc. # 5928 CODE PRINTER FUNCTION KEYING SEQUENCE CR Print Command; Carriage Return LPRINT CHR$(13) LF Full Line Feed Forward LPRINT CHR$(138) ESC SO Start Double-Width Characters LPRINT CHR$(27); CHR$(14) ESC SI Stop Double-Width Characters LPRINT CHR$(27); CHR$(15) ESC DC3 Select 10 PI Monospaced Characters LPRINT CHR$(27); CHR$(19) ESC DC4 Select 16.7CPI Monospaced Characters LPRINT CHR$(27); CHR$(20) LP-II (26-1154A) PRINCIPLES OF OPERATION The Line Printer II stores characters for printing one of two things happens: 1. Its character holding buffer is filled. 2. It receives a carriage-return code (decimal 13.) When (1) or (2) happens, the Printer prints out the contents of its character buffer. If the buffer is empty when the carriage return is received, the printer simply advances the paper one line, leaving a blank line in the printout. When operating in the 10 cpi print mode a full line of data of "buffer full" is 80 characters. When operating in the 16.7 condensed print mode a full line of data or "buffer full" is 132 characters. If more that 80 or 132 characters are received without receiving a carriage return, Printer goes "BUSY", prints the line, then goes "NOT BUSY" and gets remainder of incoming data. The printer automatically starts to print when 80 or 132 characters are received and goes into a "BUSY" mode. During print, no additional characters may be stored in the holding buffer. Printers feature an automatic line feed function. This feature automatical- ly moves the paper up one line after printing without sending a line feed character. In addition, line feeds may be used for limited paper handling functions. The printer has a special line feed buffer separate from the data buffer that holds up to 255 line feed. Each line feed moves the paper one-sixth of an inch. Thus, for example, to move the paper 12 inches would require 72 line feeds before the carriage return is sent. Line feeds within a line prior to a carriage return are all performed before printing the line. They do not cause the line of data to be printed. Normal procedures for communicating with the Line Printer II simply require that each line of data be terminated with a carriage return and be preceded with a line feed code unless the automatic line feed feature is enabled. All lines must either be terminated with a carriage return or be exactly 80 or 132 characters long to initiate the forced print of buffer full. On power-up the printer is preset to the 10 cpi print mode. To select the condensed print mode (16.7 cpi), an ESC DC4 code sequence is sent to the printer. The ESC DC4 code sequence sent within a line of data is ignored. The 16.7 condensed print mode is deselected at the end of a line or by sending an ESC DC3 code sequence to the printer. Since elongated characters may be intermixed with normal characters on the same line as described below, any lines that exceed 8 inches without a carriage return will have the excess ignored and it will not be printed. Reception of an escape code, SO sequence (or bit 87 logically high) causes all the printable characters that follow to be printed at 5 characters per inch as opposed to 10 characters per inch for normal printing. Elongated characters are simply double width characters formed by printing each print column twice. The elongation sequence is as follows: SEQUENCE DECIMAL FUNCTION ESC SO 27 14 Start Elongation ESC SI 27 15 Stop Elongation The ON/OFF switch controls the primary power. An LED, visible through the print head path, indicates that the +5 volts is active. Placing the ONLINE/OFFLINE switch OFFLINE stops all mechanical motion, resets the printer electronics, and clears the print buffer. Placing the switch ONLINE causes the printer to reset, the print head to return to the left and the electronics to go not "BUSY". CAUTION: Actuation of the ONLINE/OFFLINE switch results in loss of any data contained in the print buffer. (dkh-08/04/93)