Black Box PS035A - Manual (Page 23)

PQ-6 PLUS (RO)
22
4.4 Buffer Print Mode
A buffer print listing interprets the actions of a printer or similar device on the twinax cable. All the data that is
received is listed as a hexadecimal printout. None of the formatting commands are executed; rather, they are
printed to aid in the interpretation.
4.4.1 P RINTOUT F ORMAT
The data transmitted on the twinax cable is sent in blocks. A block can be one byte to 256 bytes long. The PQ-6
does not interpret the poll requests and device commands (such as device status) in a buffer print listing, but
prints all of the data received in each of the blocks, grouped in its block. Each byte that the PQ-6 receives is
expanded into three characters. The first two characters are the hexadecimal representation of the data byte,
and the third is the printable character that the byte would print if any. The three characters that are printed
for the received byte are printed in a vertical line. The most significant nibble on the second line, and the
printable character, if any, appear on the third line.
Characters are printed in groups of three lines, each line containing up to 128 characters. Since each block
of data can be up to 256 bytes, the blocks are printed in one or two groups of three lines. At the beginning of
each block of data, a new group of three lines starts. Thus, the position of the data within each block can be
readily seen.
Take care here if you’re using a printer that will print only 80 character lines. The groups of three lines are
up to 128 characters long. If the printer used will only print 80 character lines, or has been set to print only 80
character lines, one of two things will occur depending on the printer. If the printer is set to not auto-new-line,
the printer does an auto-new-line after reaching its line length, and the end of each line will be interlaced
between each of the original lines. You can interpret this once you realize what is happening.
4.4.2 D ATA I NTERPRETATION
The data is received in IBM EBCDIC. The format commands, while almost exactly the same for all twinax
systems, may be somewhat different. It is always best to consult the IBM manual for the particular system.
Listed next is a representation of the buffer printout. This particular listing was copied from a printout for
the beginning of the System 34 printer diagnostic. A few comments follow that will assist in its interpretation.
EXAMPLE OF A BUFFER PRINT LISTING
0
C
2C002D02002D0802C082C042C040
B62CB2490AB1310B124B222B8201
F K J a A d B H
CCCCCCCCCDDDDDDDDDEEEEEEEE44444FFFFFFFFFF
12345678912345678923456789000000123456789
ABCDEFGHIJKLMNOPQRSTUVWXYZ 0123456789