Chapter 8 P-Series Compatible Plot Mode (Odd/Even Dot Plotting)

P-Series Compatible Plot Mode (Odd/Even Dot Plotting)

This subsection describes the P-Series compatible odd/even dot Plot mode of operation. The P-Series plot has a rigid format wherein each line of data contains a plot command code, the plot data, and an LF code (hex 0A).

The P-Series codes (hex 04 and 05, respectively) can be placed anywhere on the command line.

The P-Series XQ codes (hex 04 and 05, respectively) can also be placed anywhere on the command line without degrading plot speed.

When P-Series Plot mode is enabled by an EOT (hex 04) or ENQ (hex 05) code, all control codes except LF, CR, and FF, are ignored. Any control sequence parameter prior to a plot code is acted upon immediately. Any control sequence parameter following an EOT or ENQ code is treated as plot data.

If any combination of EOT (hex 04) or ENQ (hex 05) code is received in a single line, the priority of action is:

EOT (hex 04) takes priority over ENQ (hex 05).

ENQ has the same priority level and is acted upon in the order received.

A printable symbol is defined as any character or command that might cause the head of a serial printer to move away from character column one.

Plot Density

Plot density refers to the number of dots per inch (dpi) printed in a single dot row. The dots are plot dots (not target machine dots) measuring 1/60 inch horizontally and vertically. Two types of plot density are available with P- Series Plot mode graphics: normal density and high density. The densities can be mixed within the printed page on a dot row-by-row basis, but the two densities cannot be mixed on the same dot row.

Normal density plotting is selected with the odd dot plot control code ENQ (hex 05). The odd numbered dot columns are addressed to produce a vertical density that varies based on the font selected: 72 dpi vertical for Letter Gothic (DP), and 144 dpi vertical for Courier (NLQ). Figure 31 illustrates normal density dot plot.

Figure 31. Normal Density Plot

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IBM 4400 manual Plot Density, Series Compatible Plot Mode Odd/Even Dot Plotting