The SF order is supported on all models and lets you specify
the field attributes and the display contents of a field, but not
extended attributes.
To define a field with SF, you insert a sequence in the
data stream as in Figure 1. Figure 1. Field definition using SF order
If you need to specify extended attributes, and your terminal
supports them, you use the start field extended order instead. SFE
requires a different format, because of the more complex attribute
information. Extended attributes are expressed as byte pairs. The
first byte is a code indicating which type of attribute is being defined,
and the second byte is the value for that attribute. The field attributes
are treated collectively as an additional attribute type and also
expressed as a byte pair. Immediately after the SFE order, you give
a 1 byte count of the attribute pairs, then the attribute pairs, and
finally the display data. The whole sequence is shown in Figure 2. Figure 2. Field definition
using SFE order