DMP 2102 (26-2817) Buffer Faxback Doc. # 4440 The DMP-2102'S ability to temporarily store data is one of its main advant- ages over typewriter. Codes sent to a typewriter (i.e., keys pressed) are transferred immediately to the paper. Codes sent to a Printer are not printed immediately; they are stored in a separate section of memory in the Printer call the buffer. When the buffer fills, or certain codes are received (i.e., LF or CR), the buffer is empti- ed and all data is printed on the paper. What happens after the buffer data is printed depends on the circumstances. In some cases, printing continues on the same line; in others, the Print Head is moved to a different posit- ion relative to the paper. In the DP Mode, commands for changing print fonts, Line Feed, etc., can be stored in the buffer to take affect when the data is dumped to paper. Understanding how the buffer works is important to those who wish to gain full control of the DMP-2102. HINTS AND TIPS ON THE DMP-2102 BUFFER.... * The buffer allocates a fixed number of dots depending on the character width selected. The buffer is emptied when the data stored equals that number. Printing resumes at the start of the next line. * The last character received by the buffer is printed at the start of the next print line following an automatic Line Feed and Carriage Return. * The Form Feed code (FF = 12 decimal) automatically activates printing (if the code makes it to the Printer). If LF only has been selected (Switch #5), then the buffer is printed and the print head moves to the next Top-of-Form line without a carriage return to the start of the line. Otherwise, the printing position is set at the start of the next Top-of-Form line. * The Carriage Return (CR = 13 decimal) automatically activates printing (assuming at least one character code is already in the buffer). If Car- riage Return only has been selected (Switch #6), the printing position is moved the start of the current line, but the next buffer full will print subsequent characters to the start of the next line regardless of the Switch #6. Otherwise, subsequent characters will be printed at the start of the next line. * The Line Feed (LF = 10) automatically activates printing. If LF only has been selected (Switch #5), then the buffer is printed and the Print Head moves to the next print line without a carriage return to the start of the line. Otherwise, the printing position is set at the start of the next print line. * If the computer delays more than 0.5 second before sending the next print code, the buffer is printed. Printing continues from the current position. * The Dot Positioning sequence (27 16 n1 n2) prints the buffer, if the designated position is at the left from the current position. Printing continues in the current line at the dot address specified by the (27 16) command. DATA AND WORD PROCESSING MODES ONLY: * The backspace command activates printing. Printing continues in the cur- rent line at the dot address specified by the command. * If a character set of different dot density is selected, the data in the buffer is printed. Codes for changing character sets are: 27 17, 27 18, 27 19, 27 20, 27 23, 27 29. Printing continues in the current line with the new character style. * When the start Graphics Mode (18) is received followed by the Standard or Condensed characters, the buffer is printed. * Dot graphics printing continues from the current character position. * When a start Bold or end Bold is received, the buffer is printed. * Bold printing continues from the current character position. GRAPHICS MODE ONLY: * When the end Graphics is received and returns to a Standard of Condensed character printing condition, the buffer is printed. The Printer returns to the previous print mode and printing continues in the same line from the current print position. NOTE #1: In the description, "next line" means the new line performed by Line Feed operation. In Data Processing Mode, if a Reverse Line Feed has been set in the memory, the line feed operation will cause paper to move in the reverse direction. NOTE #2: Repeat data can cause a buffer full or overflow condition, but the overflow characters are ignored and not printed at the start of the next line. (jlc-07/26/93)