User`s guide

84 DC 900-1339H
FMP Programmer’s Guide
The Raw Blocks option is always used on asynchronous lines (line mode options 2–6).
The Raw Blocks option can be used in bisynchronous mode if explicit control is needed
for message enveloping.
4.13.2 Data Records
On inbound messages with Message Blocking set to Data Records, FMP strips out block
check characters and all control characters except unit separators (which are used to
separate individual records). If a BCC error or other receive error is detected within any
record in a block, an error code is placed in the Freeway error field of the received buffer.
Figure 4–9 is an example of the Data Records setting using the sample received data
blocks shown in Figure 4–6 on page 82. There is no data blocking on unstructured
asynchronous lines.
On outbound messages, the client application places individual records in the write
buffer separated by US characters. The FMP software adds all the BSC control charac-
ters necessary to send the records in one block. In addition, FMP generates the block
check character for each record. Figure 4–10 is an example of the Data Records setting
for transmitted data.
Figure 4–8: Example of User’s Outbound Message (Raw Blocks Option)
PAD SYN SYN SYN SOH data A US BCC data B ETX BCC PAD
SOH data A US BCC data B ETX BCC
User’s Outbound Message as Sent to FMP using the Raw Blocks Option
Same Message with Characters Added by FMP Using the Raw Blocks Option