Baud Rate, Stop Bits, Parity, Response Time-Out, Ack/Nak Handshake; Errors; Things To Remember When Using Ssi Communication - Symbol DS4308 Product Reference Manual

7 - 6 DS4308/DS4308P Digital Scanner Product Reference Guide

Baud Rate, Stop Bits, Parity, Response Time-out, ACK/NAK Handshake

If you use PARAM_SEND to change these serial parameters, the ACK response to the PARAM_SEND uses
the previous values for these parameters. The new values then take effect for the next transaction.

Errors

The digital scanner issues a communication error when:
•
The CTS line is asserted when the digital scanner tries to transmit, and is still asserted on each of 2
successive retries
•
Failure to receive an ACK or NAK after initial transmit and two resends.

Things to Remember When Using SSI Communication

When not using hardware handshaking, space messages sufficiently apart. The host must not communicate
with the digital scanner if the digital scanner is transmitting.
When using hardware handshaking, frame each message properly with the handshaking signals. Do not try to
send two commands within the same handshaking frame.
There is a permanent/temporary bit in the PARAM_SEND message. Removing power from the digital scanner
discards temporary changes. Permanent changes are written to non-volatile memory. Frequent changes
shorten the life of the non-volatile memory.