User`s guide

2: FMP Protocol Summary
DC 900-1339H 29
an end-of-text (ETX) character. Each text block is followed by a block check character
(BCC) that is a redundancy check (CRC-16 or LRC-8) of the characters in the entire
block starting with the first character following SOH or STX and ending with the ETX
character. The number of SYN characters are described in Section 4.3 on page 70. PAD
characters ensure complete transmission of the data block.
An example of a market feed that uses normal BSC 3780 framing is the New Market
Reporting System from the Tokyo Stock Exchange.
The diagram below shows the same BSC 3780 message received in transparent BSC
mode. Each block starts with a data-link-escape (DLE) STX character pair (DLE STX
character combination) and ends with a DLE ETX character combination. Data within
the block can appear as any bit combination. Transparency of data is maintained by the
insertion of an additional DLE character after each DLE bit combination within the
data stream. The FMP software removes the additional DLE characters before sending
the message to the client application.
The Osaka Stock Exchange is one of the market feeds that uses transparent BSC 3780
framing.
2.1.2 Asynchronous Market Feeds
There are two basic types of asynchronous feeds: structured and unstructured. Struc-
tured feeds broadcast one text message in each block. Unstructured feeds can consist of
almost any format (or none at all). Asynchronous market feeds do not require external
clock signals to be received. However, the proper data rate option setting must be used
for each asynchronous line whether or not a modem is used. FMP handles these types
SYN SYN SOH text message ETX BCC PAD
SYN SYN DLE STX transparent text message DLE ETX BCC PAD