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USING THE NON-INTELLIGENT TERMINAL PROTOCOL
A.2.1
Errors and Error Recovery
The following ERROR RESPONSE codes from Chapter 6 relate to NITP data
link errors:
0086
0087
0089
008B
008C
008D
UNILINK HOST ADAPTER
USER MANUAL
HOST FRAME TOO LONG — the frame exceeded 590 bytes in total
length. Remember that the message body is composed of two ASCII
characters for each hexadecimal message byte. This means that your
message data can not be longer than 290 bytes which yields 580 ASCII
character bytes.
HOST FRAME TOO SHORT — the frame received was less than twelve
bytes in length. The message body must at least consist of a command
code. The frame then must be a minimum of twelve characters for the
delimiters, character count, command code message body, and ECC.
MISSED START OF MESSAGE DELIMITER — the semicolon that
begins a NITP frame was missing. Correct the frame and retransmit it.
MESSAGE LENGTH COUNT ERROR — the character count field
value did not match the number of characters received. This could be
caused by a noise spike that deletes one or more characters, or an error
in the software driver. In either case, your applications software should
retry the message at least three times. If this same error returns all
three times, check for an error in your software driver.
MESSAGE CHECKSUM BAD — the checksum calculated by the
adapter did not match the ECC field value. Retry the message at least
three times. If this same error returns all three times, check for an error
in your software driver.
INVALID HEX-ASCII CHARACTER RECEIVED — one of the ASCII
characters between the beginning and ending delimiters was not in the
NITP character set. This could be caused by noise spikes that change bit
values. Retry the message at least three times. If this same error
returns all three times, check for an error in your software driver.
A-8
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