6-38
SE-923 Scan Engine Integration Guide
Communication Summary
RTS/CTS Lines
All communication must use RTS/CTS handshaking as described in
ACK/NAK Option
ACK/NAK handshaking can be enabled or disabled. This handshaking is enabled by default
and we suggest the option not be disabled. Disabling this handshaking may lead to
communication problems, as handshaking provides the only acknowledgment to the receipt
of a message. It tells the sender whether or not the message was received, and if it was received
correctly. ACK/NAK is not used with unpacketed decode data regardless of whether or not
this option is enabled.
Number of Data Bits
All communication with the decoder must use eight bit data.
Serial Response Time-out
The Serial Response Time-out parameter is used to determine how long to wait for a
handshaking response before trying again, or aborting any further attempts
.
Both the host
and decoder should use the same value for this parameter.
Note:
A temporary change may be made to the Serial Response Time-out
when the host takes longer to process an ACK, or longer data string.
Frequent permanent changes are not recommended due to limited
write cycles of non volatile memory.
Retries
When sending data, the host should resend twice more after the initial send if the decoder
does not respond with an ACK or NAK (if ACK/NAK handshaking is enabled), or response
data (e.g., PARAM_SEND, REPLY_REVISION). If the decoder replies with a NAK
RESEND, the host resends the data. All resent messages must have the resend bit set in the
Status byte.
The decoder resends data two times after the initial send if the host fails to reply with an ACK
or NAK (if ACK/NAK handshaking is enabled).
Содержание SE 923
Страница 1: ...SE 923 Scan Engine Integration Guide...
Страница 2: ...2 70 37052 01 Rev A February 1999 Symbol Technologies Inc One Symbol Plaza Holtsville N Y 11742 1300...
Страница 3: ...SE 923 Scan Engine Integration Guide 70 37052 01 Rev A February 1999...
Страница 10: ...viii SE 923 Scan Engine Integration Guide...
Страница 16: ...xiv SE 923 Scan Engine Integration Guide...
Страница 22: ...1 6 SE 923 Scan Engine Integration Guide...
Страница 29: ...2 7 Installation Figure 2 3 Exit Window Positioning CASE 1 CASE 2...
Страница 52: ...4 8 SE 923 Scan Engine Integration Guide...
Страница 135: ...5 83 Parameter Menus Prefix Suffix Values DATA FORMAT CANCEL...
Страница 138: ...5 86 SE 923 Scan Engine Integration Guide Scan Data Transmission Format PREFIX DATA SUFFIX 1 SUFFIX 2 0x07...
Страница 155: ...5 103 Parameter Menus Numeric Bar Codes cont d 4 5 6 7...
Страница 196: ...6 40 SE 923 Scan Engine Integration Guide...
Страница 232: ...Glossary 8 SE 923 Scan Engine Integration Guide...
Страница 236: ...Index 4 SE 923 Scan Engine Integration Guide...
Страница 238: ......