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HP 27130A
ADDITIONAL OPTIONS
Six additonal options are available for special use, as follows:
1. Do not terminate the text record on errors
2. Quoting character mode
3. Conditional output separators appendage
4. Signal (interrupt) characters
S. Implicit device X -ON
6. Insert a null character into the receive buffer when a break is detected.
All six options are configured by using Write Card Configuration, Subfunction 31 (WCC, SF
31).
Error Handling
Under normal MUX firmware operation, the incoming text is terminated when any receive
data error is encountered. Furthermore, the character causing the error is added to the text record
for the host. This allows the host to detect the undesirable error condition.
If
the Do Not Terminate Text Record On Error option is enabled, the firmware will not ter-
minate the text record. The incoming character with the error will be replaced by the user-
specified replacement character which has a default value of 7FH ("DEVI). The replacement charac-
ter will be added to the text buffer and will be echoed, if echoing is enabled. The buffer, however,
will be marked "bad" when eventually terminated and sent to the host.
Under normal operation, the incoming text is terminated when any error is encountered.
Furthermore, the character causing the error is added to the text record for the host. This allows
the host to detect undesirable error conditions.
If
the lido not terminate text record on error" option is enabled, the MUX firmware will not ter-
minate the text record.
The incoming character with the error will be replaced by the user-
specified replacement character which has a default value of 7FH ("DEL"). The replacementioharacter
will be added to the text buffer and will be echoed, if echoing is enabled.
If
the "ignore parity" option in WCC, SF 13 is set, the firmware will ignore all parity error condi-
tions. The character will be processed as if no error had occurred.
Finally, if the "ignore all SIO errors" option in WCC, SF 13 is set, all received characters with an er-
ror will not be processed. However, the error bit in the termination code will be set to indicate that
an error had occurred and that characters have been discarded.
Figure 4- 2 is a flowchart showing how a received character with an error is processed.
4-16
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