LINKUP 5294 WITH DL5294 FIRMWARE
18
NOTE
The printer attached to the LinkUp must be obtained so that its device ready signal
matches the value configured in the LinkUp.
The conditions under which the LinkUp implements printer SIGNALs for an auxiliary printer are
different. Since an auxiliary printer is connected to the LinkUp by a terminal, it cannot directly
communicate with the LinkUp—it must rely on the auxiliary port provided by the terminal it is attached
to. Therefore, if the terminal cannot relay to the LinkUp the auxiliary attached printer’s off-line and on-
line states, the printer is restricted to following the off-line and on-line transmissions of the terminal.
3.3 Virtual Device Addressing
With “Virtual Device Addressing,” the LinkUp is able to support as many as 32 distinct devices. Virtual
device addressing allows the LinkUp to recognize each device that attaches to one of its ports through
a logical address; or, in other words, logical unit or LU number.
A logical unit and a physical asynchronous port are said to be coupled after you complete signing on
to the LinkUp during Connect Mode. However, being physically connected to Port 3 does not mean
you have to specify LU 3 as your assigned logical unit. Instead, by virtual device addressing, the LinkUp
allows you (and your terminal operators, providing you do not configure the asynchronous port’s
associated logical unit as non-overridable) to specify any one of the 32 supported LinkUp LUs (provided
you have configured all of them as valid in your application).
Conversely, a logical unit and an asynchronous port are said to be decoupled when a physical or logical
disconnection occurs between the attached ASCII device and the LinkUp. For example, the LU and port
are decoupled when your communi-cation line drops, or when the LinkUp times out after the
configured Inactivity Time Limit is reached. If a logical unit and an asynchronous port are decoupled,
then the formerly coupled LU can be accessed from another physical port; or another LU can be
coupled at the same physical port. In Figure 3-2, several diagrams a provided to show these various LU-
port coupling options.
NOTE
Establishing a communication link with your System/3X host for each of these LUs
means you must define a workstation identification number (also called a local session
ID or LSID), recognized as viable by your host, to each LinkUp LU. This is done by
entering your host’s LSID to the LinkUp configuration parameter of Local Station
Address.