* PI and PI/open Extended Character Set - Internal
* This swaps the mark characters with 5 control characters in the C0
* range, so that the positions normally occupied by marks can be used
* as printing characters, as follows (using ISO8859/1 descriptions):
*
*                     Internally:       Externally:
*
*    ^Z (SUB) 0x1A =  u-circumflex      Text mark
*    ^\ (FS)  0x1C =  u-diaeresis       Subvalue mark
*    ^] (GS)  0x1D =  y-acute           Value mark
*    ^^ (RS)  0x1E =  thorn             Field mark
*    ^_ (US)  0x1F =  y-diaeresis       Item mark
*
* This map can be used on internal data that is known to be in the PI/open 
* character set and known to contain the 5 G1 characters mentioned
* (for example, records in dynamic hashed files).
* See also the table PIECS-EXT for a mapping of the PI/open character
* as it applies to external data (for example, records in type 1 files).
*
1A 00FB	* Control chars become ISO8859/1 G1 characters...
1C 00FC
1D 00FD
1E 00FE
1F 00FF
FB @TM	* and these characters are the usual marks ...
FC @SM
FD @VM
FE @FM
FF @IM