The data that flows between two CICS® systems
when a CICS transaction is using a remote terminal
consists of:
- The data that is displayed on the screen. This is sent as 3270
data streams.
- Any COMMAREA and TCTUA that is saved by a pseudo-conversational
transaction when it returns.
Data conversion for transaction routing is required when the terminal-owning
region (TOR) and application-owning region (AOR) use a different code
page or byte ordering.
CICS on Open Systems and CICS on Windows Systems can be configured to convert
automatically the screen data (3270 data streams) that is sent to,
and received from, a remote CICS system. Data conversion is
triggered by the RemoteCodePageTR attribute of the Communications
Definition (CD) entry for a connection. If this attribute is set to
a code page that is different from the local code page, TXSeries for Multiplatforms ensures
that the screen data that is sent to the remote system is converted
to the code page that is specified in RemoteCodePageTR. TXSeries for Multiplatforms also
assumes that screen data that is received from the remote system is
in the code page that is specified in RemoteCodePageTR and
will convert it to the local code page. So the code page that is specified
in RemoteCodePageTR can be viewed as the code page of all transaction-routed
screen data that is flowing between the two CICS systems.
Choosing an appropriate value for
RemoteCodePageTR depends
upon the particular remote CICS system.
- IBM mainframe-based CICS does
not perform any data conversion for transaction routing. Therefore,
if your TXSeries for Multiplatforms region
is communicating with an IBM mainframe-based CICS system,
set RemoteCodePageTR to the EBCDIC code page that is used in
the IBM mainframe-based CICS system.
Your TXSeries for Multiplatforms region
does all the data conversion and the screen data flows in the code
page of the IBM mainframe-based CICS system.
- CICS OS/2 can
perform data conversion for transaction routing. However, it assumes
that all screen data is flowed in EBCDIC. If your TXSeries for Multiplatforms region
is communicating with a CICS OS/2 region,
set RemoteCodePageTR to the same EBCDIC code page as that which
is specified in the CICS OS/2 Partner
Code Page attribute of the Connection and Session Table (TCS)
entry for the connection.
- TXSeries for Multiplatforms can
receive screen data in both ASCII and EBCDIC. If your TXSeries for Multiplatforms region
is communicating with another TXSeries for Multiplatforms region,
set the RemoteCodePageTR to the same value in both regions.
For performance reasons it is sensible to make the code page that
is specified in RemoteCodePageTR the same as at least one of
the region's local code pages, to reduce the amount of data conversion.
This is not essential, however, and you can choose to use a code page
between which both regions can convert.
RemoteCodePageTR is expressed by use
of the code page names that are defined in your local machine. Table 1 shows
the code page names for your operating system. In addition, ensure
that an iconv data conversion table that can convert both ways
between the code page that is specified in RemoteCodePageTR and
the local code page, is installed on your machine. The default local
code page for the region is displayed in one of the messages that
is output in the console.nnnnnn file during region startup.
TXSeries for Multiplatforms can
convert transaction routing screen data automatically because the
structure of the 3270 data streams is well understood.
TXSeries for Multiplatforms cannot
automatically convert the data in a TCTUA or a COMMAREA that is flowed
during transaction routing because its contents are application defined.
It might contain a mixture of character and binary data that must
be converted by different techniques.
TXSeries for Multiplatforms therefore
provides a user exit called
DFHTRUC, which can be customized
to your region's applications. The default version of DFHTRUC
that is supplied with your
TXSeries for Multiplatforms region
does nothing. You might have to change it if:
- Transaction routing is being used between your region and a remote CICS system
that uses a different code page and
- Pseudo-conversational transactions that save a TCTUA or COMMAREA
when they return and are routed
- Some of the transactions that are accessing this TCTUA and/or
COMMAREA run on one system, while others run on the other
The information that follows discusses how to write your own version
of DFHTRUC.