3270 orders are included in both inbound and outbound data streams to provide
additional control function.
Table 1 lists the order codes
that may occur in 3270 data streams, and shows whether they relate to inbound
or outbound data streams, or both.
Table 1. Order codes occurring in 3270 data streamsOrder code |
Inbound |
Outbound |
Start field (SF) |
Yes |
Yes |
Start field extended (SFE) |
Yes |
Yes |
Set buffer address (SBA) |
Yes |
Yes |
Set attribute (SA) |
Yes |
Yes |
Modify field (MF) |
No |
Yes |
Insert cursor (IC) |
No |
Yes |
Program tab (TB) |
No |
Yes |
Repeat to address (RA) |
No |
Yes |
Erase unprotected to address (EUA) |
No |
Yes |
Graphic escape (GE) |
No |
No |
Note: The
3270 Data Stream Programmer’s Reference states that the SFE, SA, and MF
orders are not supported in ASCII. However, they do occur in 3270 data streams
for the EPI, where they take the following values:
SFE X'10'
SA X'1F'
MF X'1A'
Each of these orders is followed by one or more attribute
type-value pairs. The count of attribute pairs and the attribute type are
both binary values, and are thus as defined in the
3270 Data Stream Programmer’s Reference. However, the contents of the attribute
value field may vary from those defined in the
3270 Data Stream Programmer’s Reference as follows:
- If the attribute type is less than or equal to X'C0' (for example,
a color), the attribute value is defined as an EBCDIC value in the 3270 Data Stream Programmer’s Reference. The EPI uses the
ASCII equivalent of the EBCDIC value; for example, red is defined as X'F2' in the 3270 Data Stream Programmer’s Reference, and should be defined as X'32' in the EPI data stream.
- If the attribute type is greater than X'C0' (for example, field
outlining), the attribute value is a binary value. The EPI uses the values
defined in the 3270 Data Stream Programmer’s Reference.