FSS - 3270 Attribute Characters

This is a quick overview of 3270 attribute characters. An attribute character defines the characteristics of a field on a 3270 terminal. There are three types of attribute characters. The basic attribute, the extended color attribute, and the extended highlighting attribute. Each field always has a basic attribute. The two types of extended attributes are optional.

 
3270 - Attribute Byte
+-----+-----+-----+-----+-----+-----+-----+-----+
|  *  |  *  | U/P | A/N |  Display  | Rsv | MDT |
+-----+-----+-----+-----+-----+-----+-----+-----+

The value of the first two bits is determined by the value of the other six bits.

Bit 2 - Protected
Set to 0 if unprotected - the field is an input field. Set to 1 if protected - the field is output only.

Bit 3 - Alpha/Numeric
Set to 0 if alphabetic input allowed. Set to 1 if only numeric input allowed.

Skip
If both bits 2 and 3 are set to a value of 1 (Protected, Numeric) the field has the skip attribute. This means that when the cursor advances into this field as a result of typing, the cursor will jump over or skip the field and go to the next field that is not set as skip. The cursor will wrap from the bottom right corner to the top left corner if necessary.

Bits 4 & 5 - Display Intensity
     00 - Normal Intensity, Not Light Pen Detectable
     01 - Normal Intensity, Light Pen Detectable
     10 - Normal Intensity, Light Pen Detectable
     11 - Data Not Displayed

Bit 5 - Reserved - Must be 0

Bit 6 - Modified Data Tag
When set to 1 marks the field as modified and it's contents will be returned when the terminal buffer is read.

FSS - TSO Full Screen Services

3270 Attribute Characters