DMP 2100P  (260-1274)              Buffer              Faxback Doc. # 4543

The DMP-2100's ability to temporarily store data is one of its main
advantages over a 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 emptied 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 position
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-2100P.

HINTS AND TIPS ON THE DMP-2100P 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
  Carriage 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
  current 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.

(dtc-07/26/93)

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