Quantum Data 801GC, 801GF, 801GX Owner's And Programmer's Manual page 319

2250 Vertical total too small
There must be at least a total of 5 horizontal scan lines per
frame with interlaced operation.
Increase the vertical period so that it's greater than 4
lines.
Switch to non-interlaced operation.
2270 Vertical total is even
There must be an odd numbered total of horizontal scan
lines per frame with interlaced operation.
Change the vertical period (in lines) to an even number.
Switch to non-interlaced operation.
2280 Vertical total too large
The generator does not support the given vertical period.
Decrease the vertical period to less than 4096 lines
per frame if non-interlaced.
Decrease the vertical period to less than 4097 lines
per frame if interlaced.
2300 Vertical active too small
There must be at least 1 active horizontal scan line with
non-interlaced operation.
Increase vertical active so that it's greater than 1 line.
2310 Vertical blanking too small
There must be at least 1 line of vertical blanking with non-
interlaced operation.
Increase the vertical period.
Decrease vertical active.
2320 Vertical active too small
There must be at least 2 active horizontal scan lines with
interlaced operation.
Increase vertical active so that it's greater than 2 lines.
Switch to non-interlaced operation.
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