QMS 1800428-001B, Reference Manual

Page: 143 / 202

Pinout and
Cable
Specifications
3-9 Technical Specifications
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 con-
nection 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.
Macintosh Printer Cables
The following hardware, available from your QMS vendor or a local
computer store, is necessary to connect the Macintosh to the printer:
n
Two PhoneNET-type transformer boxes (one for the printer
port and one for the Macintosh port), each with a DIN-8 con-
nector
n
An RJ11 (telephone) cable
n
Two terminating resistors to close the open sockets left in the
transformer boxes after the connection is made.
PC Printer Cables
Parallel Cables
We recommend using a parallel cable if possible, because parallel
communication doesn't require printer or PC configuration, while
serial communication often does. However, if the printer is more than
6.5 feet (2 meters) from the computer, we recommend using a serial
cable for better communication.