4.Data transfer must be carried out by observing the ACKNLG or BUSY signal. (Data transfer to this printer can be carried out only after receipt of the ACKNLG signal or when the level of the BUSY signal is LOW.)

5.Under normal conditions, printer cable pins 11, 12, and 32 are acti- vated when the paper-out condition is detected. The ESCape”8” code disables pins 11 and 32, but not pin 12. Those computers that monitor pin 12 halt printing when the paper is out, making ESCape “8” ineffective.

Data Transfer SequenceInterface timing

Figure E-1 shows the timing for the parallel interface.

Figure E-1. Parallel interface timingPrinting enabled/disabled signals and control conditions

Table E-2 shows the relationship between printing being enabled or disabled, and the on-line/off-line condition, the printer select signal (SLCT IN), and the receipt of data on/off control character, DC1/DC3.

E-3