5250 Data Stream Details

AID-Generating Keys

The AID (attention indicator) code identifies to the host system the function being requested from the keyboard. The AID code is returned by certain input operations when the operator presses an AID-generating key. The following table lists the AID-generating keys and the AID codes associated with each key. See Format of the Low-Level Environment Description for instructions on how to specify an alternative help key.

AID Codes
AID key Mnemonic AID Code
Cmd 1 - 12 (cmd 1=x'31', cmd12=x'3C') QSN_F1 - QSN_F12 x'31' - x'3C'
Selector Light Pen Auto Enter QSN_SLP x'3F'
Forward Edge Trigger Auto Enter QSN_FET x'50'
PA1 QSN_PA1 x'6C'
PA2 QSN_PA2 x'6E'
PA3 QSN_PA3 x'6B'
Cmd 13 - 24 (cmd 13=x'B1', cmd24=x'BC') QSN_F13 - QSN_F24 x'B1' - x'BC'
Clear QSN_CLEAR x'BD'
Enter or Record Advance QSN_ENTER x'F1'
Help (not in error state) QSN_HELP x'F3'
Roll Down or Page Up QSN_ROLLDOWN or QSN_PAGEUP x'F4'
Roll Up or Page Down QSN_ROLLUP or QSN_PAGEDOWN x'F5'
Print QSN_PRINT x'F6'
Record Backspace QSN_RECBS x'F8'


Control Characters

The display control characters (CCs) are always specified as a pair of 1-byte fields. They are used on the QsnWTD, QsnReadInp, QsnReadMDT, and QsnReadMDTAlt APIs. These characters select specific operations for the display station to perform. Byte 1 is always processed first. When the CCs are used with the QsnWTD API, the first CC is processed immediately while the second CC is not processed until all the other information associated with the API has been processed. When used with an input operation, both CCs are processed after the operation has completed. The following two tables list the valid control character values and their associated mnemonics.

Control Character Byte 1
Mnemonic Bits 0-2 Reset Pending Aid; Lock Keyboard Clear Master MDT; Reset MDT Flags in
Nonbypass
Fields
Clear Master MDT; Reset MDT Flags in All Fields Null Nonbypass Fields with MDT On Null All Nonbypass Fields
QSN_CC1_ NULL 000          
QSN_CC1_ LOCKBD 001 x        
QSN_CC1_ MDTNBY 010 x x      
QSN_CC1_ MDTALL 011 x   x    
QSN_CC1_ CLRMOD 100 x     x  
QSN_CC1_MDTNBY_ CLRALL 101 x x     x
QSN_CC1_MDTNBY_ CLRMOD 110 x x   x  
QSN_CC1_MDTALL_ CLRALL 111 x   x   x
Note:
  1. Bits 3 through 7 are reserved and must be 0. A CPFA31C error will be issued if this is not the case.

  2. If there are no bypass fields with MDT flags on, then the master MDT will be cleared.


Control Character Byte 2
Mnemonic Bit Meaning
  0 reserved
QSN_CC2_NO_IC 1

0: Cursor moves to default or IC order position when keyboard unlocks

1: Cursor does not move when keyboard unlocks

QSN_CC2_RST_CSR_BL 2

0: no action

1: Reset blinking cursor

QSN_CC2_SET_CSR_BL 3

0: no action

1: Set blinking cursor

QSN_CC2_UNLOCKBD 4

0: no action

1: Unlock the keyboard and reset any pending AID bytes

QSN_CC2_ALARM 5

0: no action

1: Sound alarm

QSN_CC2_MSG_OFF 6

0: no action

1: Set Message Waiting indicator off

QSN_CC2_MSG_ON 7

0: no action

1: Set Message Waiting indicator on

Notes:
  • The mnemonics for control character byte 2 can be combined with a bitwise OR operation.

  • See notes in the 5250 data stream documentation for further details regarding these functions.


Screen Attribute Characters

The screen or field attributes control the image produced on the display station screen. Each attribute occupies one character position in the display station regeneration buffer and is displayed as a blank. The effect produced by an attribute begins at its location in the regeneration buffer and continues until the next attribute appears. The attributes for non-color displays are shown in the table below and for color displays in the Screen Attributes for Color Displays table. There are certain operations that allow a value to be specified for a screen attribute that indicates no screen attribute should be used. Where supported, the value is X'00' and the mnemonic is QSN_NO_SA.

Screen Attributes for Non-Color Displays
Mnemonic Bits Value
QSN_SA_NORM 0-2 001: Attribute identification flag
QSN_SA_CS 3

0: Column separator off

1: Column separator on

QSN_SA_BL 4

0: Do not blink field

1: Blink field

QSN_SA_UL 5

0: Do not underscore field

1: Underscore field

QSN_SA_HI 6

0: Low intensity

1: High intensity

QSN_SA_RI 7

0: Normal image

1: Reverse image

QSN_SA_ND   Non-display: equivalent to specifying QSN_SA_UL, QSN_SA_HI, and QSN_SA_RI.
Note: Multiple functions can be selected by combining the mnemonics with a bitwise OR operation.


Screen Attributes for Color Displays
Mnemonic Value Meaning
QSN_SA_GRN x'20' Green
QSN_SA_GRN_RI x'21' Green/Reverse Image
QSN_SA_WHT x'22' White
QSN_SA_WHT_RI x'23' White/Reverse Image
QSN_SA_GRN_UL x'24' Green/Underscore
QSN_SA_GRN_UL_RI x'25' Green/Underscore/Reverse Image
QSN_SA_WHT_UL x'26' White/Underscore
QSN_SA_ND x'27' Nondisplay
QSN_SA_RED x'28' Red
QSN_SA_RED_RI x'29' Red/Reverse Image
QSN_SA_RED_BL x'2A' Red/Blink
QSN_SA_RED_RI_BL x'2B' Red/Reverse Image/Blink
QSN_SA_RED_UL x'2C' Red/Underscore
QSN_SA_RED_UL_RI x'2D' Red/Underscore/Reverse Image
QSN_SA_RED_UL_BL x'2E' Red/Underscore/Blink
QSN_SA_ND_2F x'2F' Nondisplay
QSN_SA_TRQ_CS x'30' Turquoise/Column Separators
QSN_SA_TRQ_CS_RI x'31' Turquoise/Column Separators/Reverse Image
QSN_SA_YLW_CS x'32' Yellow/Column Separators
QSN_SA_YLW_CS_RI x'33' Yellow/Column Separators/Reverse Image
QSN_SA_TRQ_UL x'34' Turquoise/Underscore
QSN_SA_TRQ_UL_RI x'35' Turquoise/Underscore/Reverse Image
QSN_SA_YLW_UL x'36' Yellow/Underscore
QSN_SA_ND_37 x'37' Nondisplay
QSN_SA_PNK x'38' Pink
QSN_SA_PNK_RI x'39' Pink/Reverse Image
QSN_SA_BLU x'3A' Blue
QSN_SA_BLU_RI x'3B' Blue/Reverse Image
QSN_SA_PNK_UL x'3C' Pink/Underscore
QSN_SA_PNK_UL_RI x'3D' Pink/Underscore/Reverse Image
QSN_SA_BLU_UL x'3E' Blue/Underscore
QSN_SA_ND_3F x'3F' Nondisplay


Display Address

The display address is the address at which data is displayed or a field definition begins. This can be modified explicitly with a Set Output Address (QsnSetOutAdr) call, or implicitly with output operations, such as those associated with the Write Data (QsnWrtDta) API, that accept a cursor position. The 5250 Write to Display (WTD) command initializes the display address to row 1, column 1. Because each output operation contains a WTD command, this means that the display address is reset on each direct screen output operation.


Insert Cursor Address

The insert cursor (IC) order specifies the position of the cursor when the host system unlocks the keyboard and when the display station operator presses the Home key. The display address is not affected by this address. This can be set with the Insert Cursor (QsnInsCsr) API, and in some cases with the Set Cursor Address (QsnSetCsrAdr) API (only when the Move Cursor (MC) order is not supported).


Modified Data Tag (MDT) Bit

There is a modified data tag (MDT) bit for each input field and a master MDT bit. These bits are used to determine which fields should be returned in response to the Read Modified Fields (QsnReadMDT), Read Modified Alternate (QsnReadMDTAlt), and Read Modified Immediate Alternate (QsnReadMDTImmAlt) APIs. The MDT bit for a field and the master MDT bit can be set using bit 4 of the field format word (see Format of the Field Format Word) on a Set Field (QsnSetFld) API. The master MDT bit and the MDT bit for a field are set on anytime the operator types into or alters a field on the display. Once the bits are set, only a control character for resetting them (see Table 2), or a clear screen operation using the Clear Screen (QsnClrScr) API or a Start of Header order, can reset them.


Resequencing

Resequencing allows the control unit to return up to 128 input fields in any specified order. Resequencing is accomplished by chaining input fields together with Field Control Words specifying resequencing. (See Format of the Field Control Word and the 5250 data stream documentation for details.)


States and Modes

The display station can be in one of several states (conditions), each with its accompanying modes (methods of operation). The following is a list of these states and their associated modes:

See the 5250 data stream documentation for a detailed explanation of each state and mode.


Dumping the 5250 Data Stream Commands

If you wish to produce a dump of the 5250 data stream commands that are produced by the DSM APIs, you should create a physical file (using the CRTPF command) having a record length of 2000. Name the physical file QSNDEBUGF, and ensure that the QSNDEBUGF file exists in the library list. DSM will dump the 5250 data stream commands to that file.


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