Exchange/RJE Manual

Operational Features
Introduction
1–6 104698 Tandem Computers Incorporated
Operational Features As noted above, Exchange/RJE can operate in five different modes. The major
features of these modes are presented here. Both the 2780-emulation mode and 3780-
emulation modes are very similar; they are discussed together first. Following that,
the three individual block modes are discussed.
2780- and 3780-Emulation
Modes
First, the similarities between 2780-emulation mode and 3780-emulation mode are
described; then the differences between the two modes are described.
Similarities
2780-emulation mode and 3780-emulation mode share the following features:
For send operations, the maximum record size is 144 bytes.
For receive operations, the maximum record size is 146 bytes, which is the
maximum line width of a 3780 printer (144 characters) plus two bytes for vertical
forms-control escape codes.
Both emulation modes support the sending and receiving of normal text and
transparent text.
Both emulation modes automatically translate ASCII data to EBCDIC when
sending data to the remote system over an EBCDIC data communications line.
Both emulation modes also automatically translate EBCDIC data to ASCII when
receiving data from the remote system over an EBCDIC data communications line.
Automatic translation can be suppressed for transparent text if you so specify.
Both emulation modes support the truncation of trailing blanks during send
operations if you so specify.
The mode of operation (2780-emulation mode or 3780-emulation mode) is selected
at the time the connection with the data communications line is established. The
same line server can at one time emulate a 2780 terminal and at another time
emulate a 3780 terminal.
Differences
The main differences between 2780-emulation mode and 3780-emulation mode are the
following:
2780-emulation mode sends and receives blocks of up to 400 bytes in length.
3780-emulation mode sends blocks of up to 512 bytes in length and receives blocks
of up to 520 bytes in length.
2780-emulation mode uses the ITB character to separate records within a block.
3780-emulation mode uses the IRS character to separate records within a block.