Maintenance and Troubleshooting 11-5
Hex Dump
Sometimes when the printer is not printing what is expected, it is because the host is not
sending the right control sequences, or the printer emulation does not match the host
emulation. The hex dump feature shows every byte of data that is sent from the host. See
the chapter in the
Programmer’s Manual
that applies to the emulation used in order to
interpret the hex dump printout.
Choose between two presentations of hex dump: standard and enhanced. Each presentation
lists on the first line of the printout the status of certain signals on the currently selected
hardware interface. The standard presentation shows every byte of received data in
hexadecimal. The enhanced hex dump prints mnemonics in place of control codes such as
escape, carriage return, line feed, form feed, and so forth.
From the Printed Menu, find Hex Dump in Test Options, which is under Interface Parameters.
On the LCD menu, Hex Dump is under Utility.
To dump the last line, push the ON LINE key twice. Reset hex dump by cycling power to the
printer.
For example, if the printer is using one of the IBM emulations and receives the string “Mary
had a little lamb” where the word “little” is in boldface.
Mary had a
little
lamb.
The enhanced hex dump of the string above would look like the following:
BUSY HI
FAULT- LI
PE
HI
SLCT HA
SLCT IN-
A
M
a r y SP h a d SP
a SP ESC
E l i t
t
l e SP
ESC
F l a m b . CR
LF
BUSY HI
FAULT- LI
PE
HI
SLCT HA
SLCT IN-
A
From the IBM chapter in the
Programmer’s Manual,
note that ESC E turns on boldface, and
ESC F turns it off again.
Serial Interface Loopback Test
When using the serial interface, a loopback test can be run, for 80-column or 136-column as
appropriate, from the Test Options menu. (Test Options is under Interface Parameters on the
Printed Menu.) To run this test, a loopback plug (a device that allows the printer to send data
to itself) must be installed in the serial interface connector with the following pins connected:
2-3, 4-5, and 6-20. See the
Service Manual
for more details. Correct printing of the test
pattern in the loopback mode indicates that both the transmit and receive circuits in the printer
are working correctly.
