S-3
polled by the host computer.
The following information describes what happens during an XMODEM
upload:
•
After the TriCoder has received the
CONNECT
message from
the modem, the TriCoder sends out the following message to
the host computer :
PREPARE TO RECEIVE TRICODER DATA
BY XMODEM
•
Once the host begins the file transfer, the TriCoder transmits its
data in accordance with XMODEM protocol.
•
At the end of the data transmission, the TriCoder waits 2
seconds then sends out its
EOF String
(if you have one
programmed), signaling to the host that the TriCoder is ready to
continue. XMODEM does not use the TriCoder's EOF String as
an actual
End-Of-File marker
; instead, XMODEM uses the
Hex 1A
character at the end of the file.
•
The TriCoder now waits 10 seconds to receive either an
ACK
(hex 06) or an
EOT
(hex 04). An ACK (hex 06) tells the
TriCoder to retain the data file just transmitted, an EOT (hex
04) tells it to delete the data file. If the TriCoder receives either
character within the 10 seconds, the TriCoder displays the
appropriate message:
ACK, FILE SAVED
(
If ACK is received
)
Or
EOT, FILE ERASED
(
If EOT is received
)
After displaying either message, the TriCoder hangs up the
line by sending
+++ATH0
.
•
If neither an
ACK
nor an
EOT
is received by the end of the 10
seconds, the TriCoder disconnects the line and displays the
following prompt, waiting for action by the operator:
DELETE DATA FILE?
KEY [YES/NO]?
