2.“Return” denotes the twisted-pair return, to be connected at signal ground level. For the interface wiring, be sure to use a twisted-pair cable for each signal and to complete the connection on the return side. To prevent noise, these cables should be shielded and connected to the chassis of the host computer or the printer but not at both ends.

3.All interface conditions are based on TTL level. Both the rise and the fall times of each signal must be less than 0.2 microseconds.

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.)

Data Transfer SequenceInterface timing

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

Printing enabled/disabled signals and control conditions

Table F-2 on the next page 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.

Figure F-1.

Parallel interface timing

Technical Specifications

F-5