By default, GDDM resolves this ambiguity by assuming that the device is an IBM 3278. If the device is actually a nonqueriable IBM 3278 or 3279 Model 2 with an APL Feature, and if the APL character set is to be referred to by an application, the GDDM default assumption must be overridden to ensure correct operation of the device. The GDDM default can be overridden in any of these ways:

• The application can specify an explicit device token (for example, ADMK782A) on a DSOPEN call to initialize the device.

• The TSOAPLF option in GDDM's current external defaults can be modified to cause GDDM to assume by default that a nonqueriable Model 2 display terminal is an IBM 3278 or 3279. This option can be specified in one of the following places:
  • In an External Defaults Module
  • In an External Defaults File that was allocated to ddname ADMDEFS
    or
  • On a SPINIT, ESSUDS, or ESEUDS call in an application program.

  For details, see the GDDM Base Application Programming Reference book.

• Specify an explicit device token (for example, ADMK7720) in a DSOPEN call to initialize the device (see the GDDM Base Application Programming Reference book) or by means of nickname facilities (see "Coding a partial device definition for end users to change with nicknames" in topic 18.1.2).

• Use the ASTYPE call to specify the appropriate set of translation tables, as follows:

  
         Device type             Translation type number
         3277                     3277
         3277-APL                 32771
         3278, 3279               3279
         3278-APL, 3279-APL       32791
  
  

  For a description of the operation of alphanumeric translation tables, see the GDDM System Customization and Administration book.