IBM 4400 manual Plot Data Byte Format

Plot Data Byte Format

High density plotting is selected with the even dot plot control code EOT (hex

04)in conjunction with the odd dot plot control code ENQ (hex 05). The odd and even numbered dot columns are addressed to double the horizontal density. The vertical density remains the same in normal and high density plotting, though vertical density is based on the current print mode. Figure 32 illustrates high density plotting.

Figure 32. High Density Plot

Plot Data Byte Format

In P-Series Plot Mode, the format is as follows:

•Each data byte specifies six out of twelve plot dot columns.

•Using odd dot plot mode, bits 1 through 6 of the data byte address the odd-numbered dot columns; using even dot plot mode, bits 1 through 6 of the data byte address the even-numbered dot columns.

•Bit 6 and/or bit 7 of the data byte must be a “1” (or true) bit in the Plot mode.

•Bit 8 of the data byte is not used in the Plot mode and may be 1 or 0.

•The binary equivalent of the plot data bytes must be known to accurately address specific dot positions.

As shown in Figure 33, a dot is printed at the location addressed by each of bits 1 through 6 in the data byte that is set (1 or true).

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