Tag Archives: 132 column mode

Common Problems When Configuring the Inet3270 Emulator

In the IBM world, the function keys are nicely standardized but there are also differences among the terminal types used. To connect to most IBM (and compatible but not AIX or AS/400) mainframes, you would use the Inet3270 terminal emulator. Here the telnet TN3270E setting (See the Setup | Telnet menu) can have a major influence on how well you communicate with the mainframe. By default Inet3270 will run with a terminal type of IBM-3270-5. A few other options listed in the drop down box under Setup | Telnet | Terminal Type, but you may also manually edit the strings as required. For proper TN3270E connections, the mainframe might require a –E in the terminal type as in IBM-3278-9-E.

The screen layout or colour is wrong

IBM-3270 is a fairly generic name. IBM-3278 and IBM-3279 are also popular with the latter being a colour terminal. The colour instructions for an IBM-3278 and an IBM-3279 differ. The default configuration will use colours to distinguish text of various attributes even if the terminal is considered to be a monochrome terminal.

A mainframe will not send instructions to switch the terminal to 132-column mode, unless the terminal type contains a –5 as in IBM-3278-5. Your terminal will only go into 132-column mode if the proper command was sent from the server.

If you set a terminal type of IBM-3287, the mainframe will consider the terminal as a printer and may send print jobs to the terminal, which then acts as a print server.

The Inet5250 emulator is used mostly to connect to IBM AS/400 systems. The most popular and default terminal type is IBM-3179-2 with a few other options listed in the drop down box under Setup | Telnet | Terminal Type.

See also:

  • Configuring Your 3287 Printer.

Common Problems When Configuring the InetVTx00 Emulator

My function keys do not work

Depending on the termcap or terminfo file on your specific Unix host (and what is used by your application on the Unix box), you might need to change the definitions for the function keys F1 to F12. These definitions are not standardized in the Unix world. The VT220, VT300 and SCO-ANSI terminals are a bit better in this regard than VT100 or ANSI.

We recommend to try a VT220 or VT300 as a first step. The terminal type string will also influence what the application expects from the key definitions.

If you need to fix only a few keys, one approach is to try all the F-keys with Alt, Ctrl and Shift combinations to see if some other key contains the definition you need. A better method would be to look at an existing working product, to see what the definition of that key should be. But the correct method is to examine the termcap, terminfo and applications on the Unix side to see what they need.

The screen layout is wrong

Problems with the screen layout might be caused by many configurable aspects. Various operating systems and their applications have different requirements that will affect how application’s screens appear in the InetVTx00 emulator screen. Unfortunately it is impossible for us to supply a golden bullet that will work everywhere.

Please play around with these settings on the Setup | Settings dialog: the number of lines on the screen (24 or 25), the wrapping and CR/LF translations. They will solve most problems. The only other common mistake is to select the wrong screen font. The line draw characters (for boxes on the text screens) are mapped differently in different fonts. We recommend Inet or Terminal fonts. In rare cases a Courier font will also work. Do not use a proportional font like Arial or Times Roman.

To change the size of your terminal screen, first change the size of your screen font. Then you may use the View | Resize option to set the screen size optimised for your selected font.

Less common problems may relate to the VT/SCO/Ansi settings. We recommend VT on, SCO off and Ansi on for the most common scenarios. The “Scroll back Rows” is an enhancement and may confuse some applications. Set your Scroll back Rows to zero.

The color instructions sent from the server may vary depending on the terminal type used. Your terminal will only go into 132-column mode if the proper command was sent from the server. I.e.: Esc[?3h and to return to 80-column mode Esc[?3l

Once you are happy with the settings, you may save this configuration under a unique name and create a short cut to always launch and connect you to the selected host.

Hint: You may also create more than one shortcut (e.g. to connect to different hosts) using the same configuration.