Interpreters Document

Negative Response: 
Response 
Byte 
Value 
Byte Description 
1 
7F 
Negative Response Service ID 
2 
XX 
Request Service ID 
3 
XX 
Response Code 
4 
XX 
Ignored by interpreter 
5 
XX 
Ignored by interpreter 
Pseudo Code: 
XX OP AC0 AC1 AC2 AC3 G0-G1 G2-G3 G4-G5 G6-G7 G8-G9 
Get response for the request 
If a timeout occurred 
Goto No Communication Processing 
Else 
If a negative response service ID is returned (negative response service ID $7F) 
If the negative response code = expected positive response service ID plus $40) 
Set 7f-special process flag 
**(see details below) 
Endif 
Set return code to negative response code 
Else 
Set return code to positive response service ID 
Endif 
Goto response code handling 
Endif 
** Special Case 7F processing
: 
 
If the service request
has a negative response code that 
is the same as
an
expected positive response 
message response service ID plus $40: 
The 7f-special-process flag will be set. The Interpreter shall look for the 
second
occurrence of the response 
code 
in the goto fields
to determine the next Interpreter step. 
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Page
155 
(continued)
As indicated in the example below the second occurrence of the response code can occur anywhere in the 
remaining goto fields (
note
: 
For clarity,
it is recommended that the “duplicate response code” goto