User`s guide

74 DC 900-1339H
FMP Programmer’s Guide
If this option is set to disable, no data translation is performed. In this case, the client
application program is responsible for performing any necessary data translation.
The 5-bit Baudot-to-ASCII and ASCII-to-Baudot data translation using Translation
Table 3 does not work in the same way as data translation using Translation Table 1.
ASCII values that are to be translated to 5-bit Baudot code are evaluated to see whether
a figure-shift or letter-shift character should be inserted in front of the character. A
character that requires a figure-shift character inserted before it has the high bit of its
Baudot table value set. For example, if ASCII value 33 (hexadecimal) is translated to its
Baudot code equivalent, the value in the translation table would appear as 81 (hexadec-
imal). The value 81 (hexadecimal) is the Baudot 01 value with the high bit set indicating
that the character is to be preceded by a figure shift. It is the 01 value that is sent out on
the link.
On inbound data, the letter-shift and figure-shift characters are stripped from the data,
and all Baudot characters are translated to their ASCII equivalents. All figure-shift char-
acters are listed in the last 128 bytes, and all letter-shift characters are listed in the first
128 bytes of the Baudot-to-ASCII translation tables. Only data translation using Trans-
lation Table 3 employs this method; data translation using Translation Table 1 or 2 uses
one-to-one correspondence. See Appendix B for the translation tables and for an exam-
ple of data translation using Translation Table 1 or 2.
To set this option using the DLI configuration file, use the
dataTranslation parameter;
for example,
dataTranslation = “table1”. See Table 5–1 on page 104.
4.9 Data Packing Option (12)
This option controls the packing of multiple incoming records or blocks into a single
buffer. Data packing is especially useful when receiving a burst of small data blocks
from the serial line (such as test messages). In this situation the data packing feature of
FMP conserves buffer space on Freeway by packing as many of these small blocks as will