STRING CONTROL BYTE (SCB) OKLJJJJJ
o 1 Control field for data character strings Bi1§: OKLJJJJJ
--or-­
OKLJJJJJ
--or-­
o
K
L
JJJJJ
--or-­
o
K
LJJJJJ 00000000 10000000 1
o
o
1
NNNNN
1
1 NNNNN End of record
Record is continued in next
transmission block
Non-EOR SCB Duplicate character string
Duplicate character is blank
Duplicate character is nonblank
and follows SCB Duplicate count
Non-EOR SCB Nonduplicate character string
Character string length
Note: Count units are normally 1 but may be in any other units. the units used may be indicated at function control sign-on or dynamically
in the SRCB. BLOCK CONTROL BYTE (BCB) OXXXCCCC o 1 transmission block status and sequence count o
xxx
CCCC
1 000 001 010 011 100 101
110
111
NNNN
Reserved
Bypass sequence count validation
Reset expected block sequence count
to CCCC
Reserved
Reserved
Available to user
Available to user
Reserved
Module 16 block sequence count
Appendix B: MULTI-LEAVING 355

FUNCTION CONTROL SEQUENCE (PCS) ---------------- OSRRAXXXOTRRXXXB o 78 15 To control the flow of function streams 0 ••• 0 S RR ••• RR
A XXX ••• XXX T
B
1 ••• 1
o
1 00 ••• 00 1 X 1
1
Reserved (must be 1s)
Normal processing Suspend all stream transmission
(wait-a-bit)
Reserved Print stream identifier
Reserved stream identifiers
Console stream identifiers Punch stream identifiers !Qte: Function stream identifiers are meaningful only to the receiver of
the sequence. If bit Ar T, or B is off, transmission is suspended;
transmission continues when all three bits are on.
356 IBM VM/370 System programmer's Guide