Data formats

Data stream

The data is a standard outbound data stream, exactly as would be sent from the simulated terminal to z/OS® Communications Server.

Screen-image format, SLU2 mode

The data replaces, byte for byte, the data in the character buffer of the simulated terminal. Any data value is allowed. Data that goes into positions within a protected field must be identical to that in the field; data for positions occupied by an attribute byte is ignored. MDTs can be set forcibly for fields by setting the value in the attribute position to X'01'. (FEPI will set MDT automatically if data has changed.)

Key stroke format, SLU2 mode

The data can contain any combination of data characters together with manipulative, special, and attention key values. Data characters are represented by their EBCDIC code values in the range X'40'–X'FE', or by their DBCS code values of pairs of bytes in the range X'41'–X'FE', plus X'4040'. Manipulative, special, and attention key values are represented by escape sequences, comprising the escape character specified by the ESCAPE option and a 2-character code. Using & for the escape character, the escape sequences are:

Manipulative keys

&HO

home

&Ln

cursor left, n times

&Rn

cursor right, n times

&Un

cursor up, n times

&Dn

cursor down, n times

&Tn

tab, n times

&Bn

backtab, n times

&Nn

newline, n times (where n = 1–9)

Special keys

&IN

insert

&DL

delete

&RS

reset

&EF

erase to end of field

&EI

erase input

&FM

field mark

&DU

DUP

&ES

escape character

&MS

start secure MSR

&SO

shift out

&SI

shift in

Attention keys

&AT

attention

&An

PAn (n = 1–3)

&nn

PFnn (where nn = 01–24, leading 0 must be specified)

&CL

clear

&CS

cursor select (light pen)

&EN

enter

&ME

end secure MSR

Keys not listed and data characters less than X'40' are not supported. Thus, nulls (X'00') are excluded—nulls can be generated by use of the erase or delete keys. Key strokes following an attempt to enter into a protected field are ignored until reset is keyed.

For magnetic stripe reader support, the sequence &MS…data…&ME represents passing a secure magnetic stripe card through the reader. Nonsecure cards have to be simulated by using the corresponding key strokes.

Zero, one, or more than one, attention keys may be used. If an attention key is followed by data characters, FEPI does an implicit receive operation for each one until the back-end application unlocks the keyboard and sends change direction or end bracket (and FEPI responds positively to any definite response requests); then the subsequent key strokes are sent.