Chapter 4. Customizing IBM 7171 Tables
4.5 ASCII Character and Function Name Tables
While building the TDT source file, it may be helpful to refer to the following tables.
4.5.1 ASCII Character Name Table
The following table assigns a unique name to each 7-bit ASCII character. These names will be used when specifying an ASCII character in the terminal definition tables.
00 NULL 20 SPACE 40 AT 60 ACCENT
01 SOH 21 EXCLAIM 41 A 61 LCA
02 STX 22 DQUOTE 42 B 62 LCB
03 ETX 23 POUND 43 C 63 LCC
04 EOT 24 DOLLAR 44 D 64 LCD
05 WRU 25 PERCENT 45 E 65 LCE
06 ACK 26 AND 46 F 66 LCF
07 BEL 27 QUOTE 47 G 67 LCG
08 BS 28 LPAREN 48 H 68 LCH
09 HT 29 RPAREN 49 I 69 LCI
OA LF 2A STAR 4A J 6A LCJ
OB VT 2B PLUS 4B K 6B LCK
OC FF 2C COMMA 4C L 6C LCL
OD CR 2D MINUS 4D M 6D LCM
OE SO 2E PERIOD 4E N 6E LCN
OF SI 2F SLASH 4F 0 6F LCO
10 DLE 30 @O 50 P 70 LCP
11 XON 31 @1 51 Q 71 LCQ
12 DC2 32 @2 52 R 72 LCR
13 XOFF 33 @3 53 S 73 LCS
14 DC4 34 @4 54 T 74 LCT
15 NAK 35 @5 55 U 75 LCU
16 SYN 36 @6 56 V 76 LCV
17 ETB 37 @7 57 W 77 LCW
18 CAN 38 @8 58 X 78 LCX
19 EM 39 @9 59 Y 79 LCY
1A SUB 3A COLON 5A Z 7A LCZ
1B ESC 3B SEMI 5B LBRACK 7B LBRACE
1C FS 3C LESS 5C BSLASH 7C BAR
1D GS 3D EQUAL 5D RBRACK 7D RBRACE
1E RS 3E GREATER 5E UPARROW 7E TILDE
1F US 3F QUESTION 5F UNDER 7F DEL
Figure 4-6. ASCII Character Name Table
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4.5.2 Function Name Table
The following table gives a unique name to each function that can be invoked by pressing a key or key sequence on the keyboard of an ASCII terminal. The 3270 and IBM 7171 extended functions correspond to internal IBM 7171 names of sub-routines which will be called from the input parse table to execute those particular functions. Figure 4-7 lists these internal names, together with a more descriptive function notation.
Echoback Local Print Sequence
Special Character (DUP or FIELD MARK) Cursor Select (emulate light pen) Redisplay Screen Contents
Erase Input
Attention Generating (needs parameters for: ENTER, CLEAR, PF1 - PF36,
Keyboard Initiated Line Drop
Return to ENTER TERMINAL TYPE Message Alternate Keyboard Arrangement
Multiple Key Input Sequence to Graphic Character
Destructive Backspace Page Up on Logical Screen Page Down on Logical Screen Deferred Key Execute
Figure 4-7. Function Name Table
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IBM 7171 Reference Manual and Programming GuideFor a more detailed description of the 3270 and IBM 7171 extended functions refer to 3.1, "IBM 3270 Emulated and Extended Functions" on page 3-1. Most of the entries in Figure 4-7 are self explanatory. Those functions requiring addi-tional clarification are discussed briefly below:
ATTN
refers to any Attention generating 3270 key except CURSOR SELECT. CURSOR SELECT is given a separate assignment because, while certain kinds of light pen sensitive fields do generate Attentions, others only toggle the Modified Data Tag. A fourth posi-tional parameter must be provided with CALL ATTN to define pre-cisely which Attention generating key has been recognized.
is used when several keys generate sequences in which the beginning and ending characters are common and a middle key is the significant discriminator. An example of this are the IBM 3101 native PF keys (alternate functions of keys on the numeric pad). They all send a three character sequence beginning with ESC and ending with one of four optional change of direction characters (of which normally CR will be chosen). The IBM 7171 knows what function is being
requested when the middle character arrives, but it must wait until the trailing character is received. An example is provided in "Input Parse Table" on page 4-33.
allows a control key sequence to be turned into a special graphic char-acter. There are two such 3270 characters, DUP and FM, which act in many ways like graphic characters but are transmitted to the host as control characters. When a "CALL DPFM" statement is encount-ered, the P ARAM field contains a one byte value of X' 80' for the DUP character, and X' 7F' for the FM character stored in the current screen image at the current cursor position, subject to all the rules for protected fields and insert mode that apply to graphic characters.
are used to turn one of 16 special setup bits on and off. The bit number (0-15) is provided as the parameter to the SET and RESET functions. See 4.5.3, "Parameters to Pass to IBM 7171 Routines" on page 4-42 for a list of the parameters. Refer to Chapter 3, "Using ASCII Terminals on the IBM 7171" on page 3-1 for a more detailed description of these functions.
control recognition of the pacing characters defined by the RCHR string. When pacing characters are not recognized, they are treated as normal input.
selects an alternate keyboard arrangement based on the parameter value. Two keyboard arrangements are defined. When the parameter is 0 (or is omitted), the standard typewriter (QWERTY) keyboard arrangement is selected. When the parameter is 1, the Dvorak key-board arrangement is selected. Refer to Chapter 3, "Using ASCII Terminals on the IBM 7171" on page 3-1 for a more detailed description.
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MUL T allows an input key sequence to be turned into a user defined graphic character. See item 1 on page 4-64 where an example of coding this function begins.
RUBOUT is a destructive backspace function. If the cursor can move to the left and remain in an unprotected field, then the character at that location will be deleted. Any attempt to rubout a character in a protected field or an attribute byte will result in a warning beep.
PGUP is a function used to page up on a logical screen which cannot be dis-played on the physical ASCII terminal because it has a smaller screen size than the 3270 device being emulated. If the screen has been paged up as far as possible, an audible alarm ("beep") will sound.
PGDN is a function used to page down on a logical screen which cannot be displayed on the physical ASCII terminal because it has a smaller screen size than the 3270 device being emulated. If the screen has been paged down as far as possible, an audible alarm ("beep") will sound.
4.5.3 Parameters to Pass to IBM 7171 Routines
Following is a list of all possible parameters to pass to IBM 7171 routines:
Routine Parameter Meaning
DPFM X'80' Character is a D UP X'7F' Character is a FM
ALTK 1 Select DVORAK keyboard
0 Select QWERTY keyboard
DEFER routine The calling of a routine was deferred. The parameter indicates the routine that was intended.
ATTN 1 PAl was the ATTN Generating Key
2 PA2
3 PA3
4 Clear
6 Test Request
8 Cursor Select
9 Status Message Identifier
10 Enter
11 PF 1
12 PF2
... ....
46 PF 36
Figure 4-8 (Part 1 of 2). Possible Parameters to Pass to Routines
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IBM 7171 Reference Manual and Programming GuideRoutine Parameter Meaning
SET 0 Enable Zones Mode
1 3270 Null Processing
2 Reverse Enter /N ewline Keys 3 Reverse Column/Field Tab Keys
4 Allow Alphanumeric in Numeric Only Field 8 Alternate Attribute Display
9 3278 Insert Mode
RESET 0 Disable Zones Mode
1 Improved Null Processing 2 Restore Enter/Newline Keys 3 Restore Column/Field Tab Keys
4 Disallow Alphanumeric in Numeric Only Field 8 Primary Attribute Display
9 3277 Insert Mode
Figure 4-8 (Part 2 of 2). Possible Parameters to Pass to Routines
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4.5.4 ROM Pointers to Internal Information
At the start of ROM, there is a list of addresses to all of the standard IBM 7171 information. The following is an abbreviated list of that information. For a full description refer to Appendix E, "ROM Data Base Organization." The user is advised to use the information found here as often as possible. The addresses can be found using the Maintenance Facility, described in Chapter 9.
Index Address Pointer
8000 4000 Address of IBM3101 TDT