VT510 Video Terminal Programmer Information

DECPAK—Program Alphanumeric Key

Allow users to reprogram keys to transmit user-preferred alphanumeric codes or to perform user-preferred functions.


D . . . D


This sequence programs one or more keys (and their modifiers) to:

This function works in all the VT modes except in VT52 mode.

The memory allocation and deallocation processes (program key lock and unlock process) on the DECPAK are the same as on the DECPFK. Refer to DECPFK—Program Function Key for details.

The data string D...D format is:

Key1/HEX Code String/Function #/UDS/UDS Direction;Key2/...;


is the key station number and slash "/" is a delimiter.

HEX code string
is the hex character code to be transmitted with each of the seven modifier states. The hex code represents a valid code in the current character set (either 7-bit or 8-bit). Use a period "." as a place holder if a modifier combination is not to be defined. Use a minus "-" preceding the hex representation of a diacritical sign if a diacritical mark is to be defined.

The terminal always allows the ISO character set to be used for specifying accent marks to DECPAK even when:

  1. 7-bit NRCs characters are selected
  2. The ISO character set is not the user-preferred supplemental character set

The corresponding ISO character set would be based on the keyboard language. Refer to Chapter 8 for keyboard information.

The position of the diacritical marks within the ISO Latin character sets is as follows:

Diacritical Sign Position Available ISO Character Set(s)
Circumflex 5/14 ASCII
Grave 6/0 ASCII
Tilde 7/14 ASCII
Dieresis (umlaut) 10/8 Latin 1, Latin 2, Latin Greek, Latin Turkish
Degree (ring) 11/0 Latin 1, Latin 2, Latin Greek, Latin Turkish
Acute 11/4 Latin 1, Latin 2, Latin Greek, Latin Turkish
Cedilla 11/8 Latin 1, Latin 2, Latin Turkish
Macron 10/15 Latin 1
Breve 10/2 Latin 2
Ogonek 11/2 Latin 2
Caron 11/7 Latin 2
Double Acute Accent 11/13 Latin 2
Dot Above 15/15 Latin 2

You should program the Hex string according in the following order:

  1. Group 1 unshifted
  2. Group 1 shifted
  3. Group 1 alternate shifted (Shift 2)
  4. Group 2 (Group Shift or Alt Gr) unshifted
  5. Group 2 shifted
  6. Group 2 alternate shifted
  7. Control (if omitted, use default)

If the control state is not redefined in this sequence, then the Key/Ctrl combination generates the control code based on the "Group 1 unshifted" state.

A graphic key transmits alphanumeric codes only when pressed with the above modifiers. When pressed with Alt key, the graphic key performs either:

Function #
corresponds to a local function to be performed when the key is pressed in combination with the Alt function. Example: Function number "0" is used to make the Key/Alt combination inoperative. Function number "100" indicates a user-defined sequence (UDS), and a UDS direction is defined for the Key/Alt combination following the "/" delimiter.

UDS and UDS direction
is a user-defined sequence. These parameters are the same as for DECPFK. Refer to DECPFK—Program Function Key for the details.

Once programmed, the key states are not affected by the terminal mode changes. Refer to DECPFK—Program Function Key for the list of terminal mode changes.