SSI Interface 8 - 5
ACK/NAK Disabled and Packeted DECODE_DATA
In this example ACK/NAK does not occur even though packeted_decode is enabled because the ACK/NAK
handshaking parameter is disabled.
ACK/NAK Disabled and Unpacketed ASCII Data
Data captured by the digital scanner is sent to the host.
Communication Summary
RTS/CTS Lines
All communication must use RTS/CTS handshaking as described in the Simple Serial Interface Programmer’s
Guide, p/n 72-40451-xx. If hardware handshaking is disabled or bypassed, the WAKEUP command must be sent
prior to all other communications, or the first byte of a communication message may be lost during the digital
scanner wakeup sequence.
ACK/NAK Option
Enable or disable ACK/NAK handshaking. This handshaking is enabled by default and Zebra recommends leaving
it enabled. Disabling this handshaking can cause communication problems, as handshaking is the only
acknowledgment that a message was received, and if it was received correctly. ACK/NAK is not used with
unpacketed decode data regardless of whether or not it is enabled.
Number of Data Bits
All communication with the digital scanner must use 8-bit data.
Decoder
Data is captured
by decoder
Host
(1)
DECODE_DATA
message sent
Decoder
Data is captured
by decoder
Host
(1)
ASCII data sent