HP 8921A Programmer's Manual page 513

SID1
RSVD
NAWC
OHD
Parity
First part of the system identification field. The field contains the decimal equivalent of
the 14 most significant bits of the system identification number.
14 binary characters required.
Reserved for future use.
3 binary characters required.
This field displays the number of additional words coming.
4 binary characters required.
This field displays the overhead message type.
• A '100' indicates a global action message.
• A '110' indicates that this is the first word of the system overhead parameter message.
• A '111' indicates this is the second word of the system parameter overhead message.
3 binary characters required.
Parity field. The contents of the Parity field cannot be set by the user. The Test Set
calculates the parity bits.
Chapter 8, Programming The Call Processing Subsystem
CALL BIT Screen Message Field Descriptions
513