QMS 860, User Manual, Page: 297 / 398

Notes to the Centronics Parallel Cable Pinouts Table
Direction refers to the direction of signal flow as viewed from the
printer.
Return denotes “twisted-pair return” and is to be connected at
signal-ground level. When wiring the interface, be sure to use a
twisted-pair cable for each signal and never fail to complete
connection on the return side. To prevent noise effectively, these
cables should be shielded and connected to the chassis of the system
unit and printer, respectively.
All interface conditions are based on Transistor-Transistor Logic
(TTL) level. Both the rise and fall times of each signal must be less
than 0.2 microseconds.
Data transfer must be carried out by recognizing the ACKNLG or
BUSY signal.
The cable must have an overall braided shield, Belden 8345 or
equivalent.
Connectors must have shielded housings. The overall shield must
be bonded to the shielded housings at both ends of the cable.
Appendix A
C a b l e P i n o u t s A - 3