Epson LQ-2550 - Impact Printer Product Support Bulletin page 16

EPSON
EPSON AMERICA, INC.
SERVICE
PSB NO.: P
-
SUBJECT: CENTRONICS PARALLEL REQUIREMENTS TO ELIMINATE RANDOM
CHARACTERS USING THE LQ-2500 AND LQ-2550
The purpose of the bulletin is to resolve the problem of random
characters generated by the LQ-2500 and the LQ-2550.
received numerous reports from the field regarding this problem.
After intensive testing, the problem was isolated to improper
Centronics parallel cables.
were:
(1)
Unsuitable shielding - some cable manufactures neglect
to include the twisted pair grounds.
without proper shielding allow electronic fields to
affect the data transfer, thus causing extraneous
characters.
protect against external noise.
Unacceptable use of parallel communications - The
recommended length of a parallel cable is 6 to 10 feet
long.
the flow may become inconsistent causing random
characters to be printed.
10 feet in length serial communications is recommended.
If the two issues noted above are corrected, the majority of the
problems regarding random characters should be eliminated.
Proper shielding should always be verified before any other work
is initiated.
manufactured without shielding to help keep production costs
down.
The length of a Centronic parallel cable should be kept
a maximum of 10 feet for optimum performance.
to
transmission over 10 feet in length serial communications is
recommended.
EPSON AMERICA SERVICE, 23610 TEL0 AVENUE, TORRANCE, CALIF, 90505
P
RODUCT
DATE: 10/04/88
0 0 3 1
Shielded cables encase the data lines to
When a parallel cable is longer than 10 feet,
Many of the older inexpensive cables were
S B
UPPORT ULLETIN
The types of problems encountered
For data transfer over
PAGE: 1 of 1
We have
The cables
For data