Reference Guide

SSI Interface
186
Transfer of Decode Data
The Decode Data Packet Format parameter controls how decode data is sent to the host. Set this
parameter to send the data in a DECODE_DATA packet. Clear this parameter to transmit the data as raw
ASCII data.
ACK/NAK Enabled and Packeted Data
The digital scanner sends a DECODE_DATA message after a successful decode. The digital scanner
waits for a programmable time-out for a CMD_ACK response. If it does not receive the response, the
digital scanner tries to send two more times before issuing a host transmission error. If the digital scanner
receives a CMD_NAK from the host, it may attempt a retry depending on the cause field of the CMD_NAK
message.
ACK/NAK Enabled and Unpacketed ASCII Data
Even though the ACK/NAK handshaking is enabled, no handshaking occurs because the handshaking
applies only to packeted data. In this example the packeted_decode parameter is disabled.
note When transmitting decode data as raw ASCII data, ACK/NAK handshaking does not apply regardless of
the state of the ACK/NAK handshaking parameter.
Decoder
Data is captured
by decoder
Host
(1)
DECODE_DATA
(2)
CMD_ACK
message sent
Decoder
Data is captured
by decoder
Host
ASCII data
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