EM3270 Manual

Product Components and Operation
Tandem EM3270 Manual—110332 1-13
PCT Color Mapping
In PCT versions G40 and later, several enhancements were implemented that enable
EM3270 to overcome most of the architecture differences between the 3270 and the
6530.
Tandem terminals delete trailing spaces in fields; that is, these terminals consider a
trailing space to be identical to a null character. The EM3270 emulator defines a SPACE
function key for inserting trailing spaces. The shifted ROLL DOWN key is mapped to
the SPACE function in the Tandem terminals. You can use the SET DEVICE
BLANKFIELD command options to direct the EM3270 emulator to not add trailing
spaces, add one space, or fully pad a field with spaces. This command only applies to
fields that do not contain non-blank characters.
The SPACE key and BLANKFIELD parameter are not required when using PCT
version G40 or later, since PCT handles blank and null characters the same as a 3270
device.
File Transfer During a Dual-Application Session
A personal computer fully emulating a Tandem terminal assumes the capabilities of a
workstation in relation to the EM3270 emulator. When the EM3270 emulator is
configured for a dual-application session, the NonStop Kernel TRANSFER/MAIL file
transfer feature is available to the workstation user. While a workstation is controlled by
the EM3270 emulator, the user can invoke TRANSFER/MAIL to send and receive files.
TRANSFER/MAIL calls IXF (information transfer facility) to transport data files to and
from the workstation’s storage.
During file transfer, IXF requires that the workstation be in conversational mode. This
destroys its screen buffers. To compensate, the EM3270 emulator saves the content of
the host screen and restores it following completion of an IXF transfer. TRANSFER/
MAIL then refreshes its screens.
PCT Color Mapping
The EM3270 emulator maps color data streams to the color support provided in PCT
and OV/TTE. Depending upon the setting of the device parameter COLOR, mapping is
automatic or is performed in a user-exit routine. If COLOR is set to OFF or
EXTENDED, EM3270 performs automatic mapping. If COLOR is set to ON, the user-
exit routines are called to perform the color mapping. The user-exit routines are also
useful when using Tandem terminals that do not support color. On such devices, you
can use video highlighting.
The EM3270 emulator provides this support by mapping various combinations of 3270
attributes to PCT attributes. PCT permits color selection using the five video bits,
providing 32 color combinations. You associate these attribute combinations with
particular colors in the PCT.INI file.
The EM3270 emulator provides three user-replaceable procedures that control color
mapping for base and extended color support: they are listed in Appendix E, “Color-
Mapping and Function-Key Mapping.” The PCT.INI configuration file is used to
associate particular colors with various combinations of the five video bits.