set to zero
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... connection was not accepted.
The source reference field in the DR TPDU is set to zero to indicate
an unassigned reference.
...
... its variable part. The value field of the checksum parameter must be
set to zero at this point.
2. Initialize two variables to zero. Let these variables
...
... Note: The credit field of the AK TPDU is
not used in this class (always Set to zero).
o use of network ...
... given direction of data transmission after the connection
establishment has a TPDU-NR field set to zero).
Receipt of a Data TPDU whose TPDU-NR ...
... Parameter value encoded as a sequence of single
octets. Each octet is encoded as for octet 7 but with bits 4-1 set
to zero (i.e., no alternative option selections permitted).
o Acknowledge Time
...