Visara LINCS Features - Manual (Page 113)

103 707021-001
8. DFT Devices
A DFT is a coax device that processes its own data stream and performs some of the protocol
functions. Since these devices also process their own keystrokes, some of the LINCS features
normally available to CUT devices are not supported by DFTs.
DFTs can have up to five DFT host sessions. In a BSC or nonSNA channel environment, all
DFT sessions must be on the same host. In a SNA environment, all five DFT sessions may be
on the same or different hosts.
DFT-E
DFT-E devices are extended DFTs which can simultaneously support a CUT session in addition
to five DFT sessions.
The CUT session may be assigned any type of LINCS host session including both ASCII and
3270 hosts. This session will support most features of a standard non-EAB MOD 2 CUT
device, except for windowing and CUT-type printer functions. A local DFT printer is supported
when configured as a DFT LU.
DFT-E Configuration
Configuration - Sessions A through E are configured as standard DFT sessions. Session F
will be treated as the CUT session, even if fewer than 5 DFT sessions are configured.
Downstream Loadable (DSL) Devices
DSL devices are DFTs that load their control program from a LINCS disk. A floppy disk that
contains the DSL control program must be obtained from the manufacturer of DSL device.
The DSL files may optionally be merged to the LINCS hard disk using the DSL merge
procedure. The IBM 3179G, 3192G, 3193, 3290, 3472G, and PS/2 are examples of DSL devices.
RTM
LINCS supports RTM on DFTs. However, because DFTs perform their own keystroke and
datastream processing, RTM support is also required within the DFT. Before you attempt to
use RTM with a DFT, you should verify that RTM support is available within the device.
A LINCS node and an attached DFT communicate in the following manner to provide RTM
support:
• When the DFT is powered on (or the host changes RTM parameters), LINCS notifies the
DFT of the RTM configuration parameters.
• The DFT asks LINCS to start the RTM timer when an AID key is pressed.
• After the host has responded to the AID (based on the current RTM end of transaction
definition), the DFT asks LINCS to stop the RTM timer.
• If authorized, LINCS then updates the RTM log and the LTTI for the device. If authorized,
the DFT displays the LTTI.