Chapter 15: Configuring Terminals and Printers

This chapter describes how to set up and configure terminals and printers for the CICS Option component of Mainframe Express.

Overview

The user interface to CICS Option applications from the PC is through 3270 terminal emulators. The 3270 terminal emulators enable CICS Option to display CICS application input and output screens on the PC using 3270 data streams and to receive input from the PC.

When you start a 3270 terminal emulator, it is installed into a CICS Option region. The parameters that describe the terminal are determined either by a set of default rules, or by an autoinstall control program (ACP). CICS Option uses autoinstall to install terminals; if you want to configure or control the way autoinstall behaves, you can supply an ACP.

This chapter describes the default installation parameters and the steps needed to implement user autoinstall on a region, as well as the details of the ACP interface.

You can also connect 3270 terminal emulators running on other multi-tasking Windows NT machines to CICS Option over a network.

You can also connect a third-party Telnet 3270 (TN3270) terminal emulator, by defining it on the Communications tab of the SIT Properties dialog box. For more information see the section Telnet 3270 Terminal Emulators.

Terminal Emulator Installation

CICS Option does not require a Terminal Control Table entry to be defined for each terminal. Instead, it creates an entry dynamically each time a user starts a 3270 terminal emulator.

When you start a terminal emulator, it passes a set of parameters to the autoinstall program. These can all be set from the Mainframe Express IDE, except for the screen size, which the emulator picks up automatically from its environment.

CICS Option then builds a Terminal Control Table entry from the parameters supplied in one of two ways:

• The parameters are used directly to install the terminal (this is the CICS Option default).
• The parameters are passed to the autoinstall process, which selects an appropriate model terminal definition.

Autoinstall provides you with greater flexibility in defining terminals, but requires some work to implement (see the section Implementing the Autoinstall Exit).

Example Terminal Definitions

The resource definition file supplied with CICS Option contains a group, DFHTERM, which contains example 3270 terminal definitions. The supplied group contains the following definitions:

If you want to use one of these definitions, you must include the group DFHTERM in the startup list for the project, as follows:

1. Click the CICS tab on the Project View.
2. Right-click on CICS System to display the associated context menu.
3. Click Startup List to display the Startup List Configuration dialog box.
4. Check whether the group DFHTERM is in the left-hand list of Groups in Startup List. If not:
   1. Select the group from the right-hand list.
   2. Click << Add to move it to the left-hand list.
   3. Click OK to confirm the move.

To select one of these terminal definitions, you use the Configure Default Terminal dialog; either:

1. Click CICS on the Tools menu of the IDE.
2. Click Region Management.
3. Click Configure Default Terminal.

or:

1. Click Start Debugging on the Debug menu of the IDE.
2. Click the CICS tab.
3. Click Configure Default Terminal.

If you are using a multi-tasking region and would like multiple 3270 terminals connected to the same region to use the same terminal definition then you must select Model in Based on and specify the model name you require from the table above in Name. The termid and netname will be assigned automatically during auto-install.

If you require a particular termid or netname or have no requirement to share the terminal definition then you should select Netname in Based on and specify the netname you require from the table above in Name. The termid and netname you specified will be assigned during auto-install. If the netname is already in use then the the auto-install process will fail.

Terminal Installation Parameters

When a 3270 terminal emulator starts, it passes a set of parameters to CICS Option. These are either used to install the terminal directly, or passed to the autoinstall process.

The parameters passed to autoinstall are:

Configuring the Autoinstall Exit

The supplied autoinstall exit DFHZATDX selects the best model definition match based on screen size. If you write your own autoinstall program you can select the model and change other parameters such as the terminal ID.

Implementing the Autoinstall Exit Program

To implement autoinstall in a region you can use the supplied autoinstall exit DFHZATDX or you can specify your own autoinstall control program (ACP).

To use your own ACP you must:

1. Write an Autoinstall Control Program (ACP).

   The interface to ACP is fully defined below. Put the executable file for the program on the program path. The Autoinstall Processing section describes the flow of information between the ACP and a CICS Option region.

2. Enter the ACP program name in the AI Exit field in the SIT.

   Information on updating the SIT is available in the online help; click Help Topics on the Mainframe Express Help menu, then on the Contents tab click CICS Option, Defining Resources, How to View and change the SIT. You should be aware that the autoinstall exit interface is designed to be an ASCII interface. The autoinstall exit you specify in the AI field in the SIT must be a program compiled with the CHARSET(ASCII) Compiler directive.

3. Define one or more terminal models from which the ACP can select (see the section Terminal Models later in this chapter).

Autoinstall Interface

You should write an ACP that is supplied with:

• Default installation parameters
• A list of compatible terminal models

The control program returns:

• A single terminal model name
• A terminal ID
• A printer ID
• An alternate printer ID
• A status byte, which must be set to LOW-VALUES. If not, the terminal is not installed.

Autoinstall Control Program Call Interface

The ACP has the following call interface:

ENTRY ai-prog-name USING a-string pointer-1 pointer-2
       pointer-3 pointer-4

where:

The remaining parameters are part of DFHCOMMAREA as follows:

01  DFHCOMMAREA
    03 a-string     PIC X(4).
    03 pointer-1    POINTER.        pointing to Net-Info.
    03 pointer-2    POINTER.        pointing to Model-table.
    03 pointer-3    POINTER.        pointing to TCT-Info.
    03 pointer-4    POINTER.        pointing to Term-Info.

where:

This data format and those for pointer-1, pointer-2, pointer-3, and pointer-4 are supplied in copybook dfhcwai.cpy.

Pointer-1

Pointer-1 points to memory block 1.

Data Format:

Memory block 1 is passed to the ACP with data in the following format:

01  Net-info.
    03 name-length      PIC X       COMP-X.
    03 netname          PIC X(8).

where:

Pointer-2

Pointer-2 points to memory block 2.

Memory block 2 is passed to the ACP containing the list of suitable autoinstall models for the physical screen.

Data Format:

01  Model-table.
    03 table-name-count     PIC X    COMP-X.
    03 autinst-name-1       PIC X(8).
        

You can include between 1 and 100 entries of autinst-name-n, depending on table-name-count.

where:

The memory block contains table-name-count autoinstall entries.

Pointer-3

Pointer-3 points to memory block 3. The ACP uses memory block 3 to return information enabling CICS Option to create a TCT entry and log the terminal on to the system.

Data Format:

01 TCT-Info. 
    03 autinstname          PIC X(8). 
    03 terminal-id          PIC X(4). 
    03 printer-id           PIC X(4).
    03 altprinter-id        PIC X(4). 
    03 status-byte          PIC X(1).

where:

Pointer-4

Pointer-4 points to memory block 4.

Data Format:

Memory block 4 contains data in the following format:

01 Term-Info. 
    03 term-info-length     PIC X   COMP-X. 
    03 height               PIC X   COMP-X. 
    03 width                PIC X   COMP-X. 
    03 uctran-setting       PIC X.

where:

Autoinstall Processing

This section explains the process and information flows when a user starts a 3270 terminal emulator from the Mainframe Express IDE.

Figure 15-1 illustrates the steps in the autoinstall process.

Figure 15-1: The autoinstall process

1. The autoinstall process receives information from the terminal installation parameters.
2. The autoinstall process builds a list of models (from resource definitions in the terminal control table), with screen sizes compatible with the physical terminal (see the section Screen Sizes).
3. The autoinstall process calls the ACP, supplying it with the following information:
   • The list of autoinstall model names
   • The physical screen size
   • The netname
   • A suggested terminal ID (last four characters of the netname)
   • Whether or not UCTRAN was set
4. The ACP returns the parameters that CICS Option needs to create a terminal control table entry dynamically. These are:
   • Terminal ID
   • Terminal model name

   The ACP also supplies the name of a printer and alternate printer to be associated with the terminal.

5. CICS Option dynamically creates a terminal control table entry, using the returned parameters and the terminal model definition.

Terminal Models

A terminal model enables you to define a terminal more fully than the default parameters supplied at terminal startup (see the section Terminal Installation Parameters earlier in this chapter). A terminal model can also override some, but not all, of the defaults supplied at startup.

Defining Terminal Models

The steps to define a terminal model are outlined below. You must use the character interface to resource definition (click Resource Definition from CICS on the Tools menu) to define the terminal and typeterm entries. Within resource definition you can get help information on each field by pressing Alt+F1=help.

1. Create a new entry in the terminal control table. (Press F7=group resources, enter group name, press F9=terminal/connection and press F2=terminal/model.)
   • For a model defined as Model: Only, you must specify:
     • A model name. This is the name you specify in the Name field for the Model option of the Based on field on the Configure Default 3270 Terminal dialog box.
     • The name of a typeterm entry
   • For a model defined as Model: Yes, you must specify:
     • A model name
     • The name of a typeterm entry
     • The netname. This is the name you specify in the Name field for the Netname option of the Based on field on the Configure Default 3270 Terminal dialog box.
   • A model defined as Model: No is a physical terminal definition and you must specify:
     • The name of a typeterm entry
     • The netname
2. Create a matching typeterm entry (if none exists). (Press F7=group resources, enter group name and press F10=typeterm.) At a minimum, this must specify:
   • Screen size (rows by columns)

   Many different models can refer to the same typeterm entry.

Startup Overrides

A terminal model can override some, but not all, of the parameters defined in the section Terminal Installation Parameters.

The list below shows the scope of what a terminal model can do:

Defining a TCT User Area (TCTUA)

You can define a TCTUA in several ways. In each case you must define the terminal and typeterm entries using the character interface to resource definition - click CICS on the Tools menu of the IDE, then click Resource Definition. From the main menu, press F7, enter the group name, press Enter. From this menu either press F9 followed by F2 to define the terminal model, or press F10 to define the typeterm.

1. Define a terminal with the following parameters set:
   • Model: Y
   • Auto-install Model Name: MODTCTUA
   • Term Type: TCTUATYP (this must be specified and must correspond to the typeterm name)
   • Net name: NETTCTUA
   • INSERVICE: Y
   • CONNECTION TYPE: TERMINAL

   You must then define a typeterm and set the terminal type to the name you supplied in the Term Type field of the terminal definition (TCTUATYP in the example above). You should also set the User Area Size field (a value from 1 to 255). You must also enter Y in the Uppercase Translation field if you require uppercase translation.

   Either:

   Start the terminal specifying NETTCTUA as the netname and it will use this terminal definition. (This can only be used for one terminal in a multi-tasking system so is only recommended for the single-tasking system.)

   or:

   Start the terminal specifying MODTCTUA as the model name and it will use a terminal definition modelled on the TCTUATYP typeterm.

2. Define the terminal and typeterm as above and specify an AUTOINSTALL exit name of DFHZATDX. When you start either the single-tasking system or a 3270 terminal the model which closest matches the physical screen size will be used automatically.
3. Define the terminal and typeterm as above, but define your own autoinstall user exit. Samples of this are the supplied autoinstall exits dfhuains.cbl and dfhuain2.cbl.

   If the Model is specified as "Y" then a netname is required. However if a model is set to "O" - Model only, then no netname is required.

Screen Sizes

CICS Option supports displays of up to 132 columns by 31 lines (a maximum of 4096 characters). The standard screen sizes are:

Whenever you start a 3270 terminal emulator, it passes the physical screen size to the autoinstall process, deducting one line from the length to allow space for the status line.

The autoinstall process treats any screen size defined in the typeterm as compatible if it is no more than one line longer than the physical screen size as defined by the terminal emulator program. That is, there are enough lines for the data, but no separate line for the 3270 status line.

The terminal emulator handles the status line in different ways, depending on whether the physical screen can display it on its own separate line or not. This is covered in the next section.

The Status Line

3270 terminal emulators have four status line display modes, through which the end-user can cycle by pressing Alt-T:

Light Pen Support

Light pen support is provided through a mouse simulation of the light pen facility.

Activating Light Pen Support

If you do not have your own autoinstall exit, use the character interface to resource definition (click Resource Definition from CICS on the Tools menu) and:

• Enter DFHZATDX in Auto install exit on the System page of the SIT Properties dialog box.
• Using the character-based CICS Resource Definition facility, create a Typeterm entry named LPENTYPE and enter Y in the lightpen field on screen 2.
• Create a terminal entry (Z999 for example) with at least the following specified:

If you have your own autoinstall exit you should ensure that light pen is specified in the terminal model you use.

Operating Light Pen Support

Mouse button 1 (left button) positions the cursor at the indicated character

Mouse button 2 (right button) behaves as follows:

• If a field does not have the light pen attribute selected the alarm will sound.
• If a field does have the light pen attribute selected the following will occur:
  • The modified data tag (MDT) bit will be inverted.
  • If the first character of the field is a space, a light pen attention will be generated.
  • If the first character of the field is a "?", it will be changed to a "".
  • If the first character of the field is a "", it will be changed to a "?".

Double clicking mouse button 1 is equivalent to one click of mouse button 2.

Telnet 3270 Terminal Emulators

CICS Option includes an interface to enable use of a TN3270 terminal emulator in place of the built-in 3270 terminal emulation. This enables you to use the same terminal emulators that you use to connect to your mainframe CICS system. The TN3270 emulator session can run on the same machine as Mainframe Express or on a network machine.

You specify that you want to use a TN3270 terminal emulator on the Communications tab of the SIT Properties dialog box. Check Enable gateway in the TN3270 group to enable the use of a TN3270 terminal emulator. Then specify the TCP/IP port number used by the terminal emulator in Port number. This is usually 23.

By default CICS Option installs TN3270 terminals dynamically as basic 3270 terminals. This means that some of the more advanced features of your TN3270 terminal emulator won't be available. To make these features available, you need to enable CICS Option to associate the TN3270 device type and a CICS typeterm definition.

The TN3270 device type is specified by the emulator software and might or might not be configurable. Device types indicate the ability of the emulator to support various elements of the 3270 data stream, for example, color, extended attributes, the use of a TCTUA etc.

During the connection negotiation the TN3270 client sends a data packet indicating which device it wishes to emulate. CICS Option uses this data to identify a typeterm entry which defines this terminal type.

To make this work you need to:

1. Define a typeterm entry that matches the capabilities of the TN3270 terminal emulator.
2. Define a terminal model entry which points to this typeterm definition. Required fields for the terminal model entry are:

   Terminal id	Unique name of this terminal model
   Auto install model	O(nly) or Y(es)
   Auto install name	The TN3270 device type
   Term type	The name of the typeterm entry to use with this terminal

For example, suppose the TN3270 client software is configured to emulate an IBM 3279 MOD2 with support for extended attributes. At connection time CICS Option searches for a terminal model entry with the name TN32792E. The terminal type specified in this terminal entry is then used to look up the terminal's details in the termtype entry .

If you want to use a screen size other than the default, which is MOD2 (24 by 80), you also need to:

1. Specify the screen size in the Alt screen field of the typeterm entry (screen 2).
2. Set the environment variable TX_TN3270_FORCE_ALT=Yes before starting Mainframe Express.

Printers

You can use a printer device for 3270 printer support. Printer support is handled by 3270 printer emulators, which interpret the 3270 printer data stream and send it to a system printer.

To start a printer emulator in a CICS Option multi-tasking region, you must enable printer support. To do this update the following fields in the SIT using the character interface to resource definition (click Resource Definition from CICS on the Tools menu):

The CICS Option multi-tasking region starts a printer emulator for each entry in the terminal table which is:

• Set as MODEL=NO (the netname must be defined)
• Has a Termtype entry which specifies a 3270 printer (3270P)

The netname defined in the terminal table must be unique to the region. The terminal ID for the printer is taken from the terminal definition.

To avoid conflicts with automatically assigned netnames (see the section Terminal Installation Parameters), you should assign netnames to printers counting downwards: PRNZ999, PRNY999 ... PRNA000.

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