Software Handshaking - Motorola Symbol LS3408 Product Reference Manual

RS-232 Interface 6 - 13

Software Handshaking

This parameter offers control of the data transmission process in addition to, or instead of, that offered by hardware
handshaking. There are five options.
If Software Handshaking and Hardware Handshaking are both enabled, Hardware Handshaking takes
precedence.
None
When this option is selected, data is transmitted immediately. No response is expected from host.
*
None
ACK/NAK
When this option is selected, after transmitting data, the scanner expects either an ACK or NAK response from the
host. When a NAK is received, the scanner transmits the same data again and waits for either an ACK or NAK.
After three unsuccessful attempts to send data when NAKs are received, the scanner issues an error indication
and discards the data.
The scanner waits up to the programmable Host Serial Response Time-out to receive an ACK or NAK. If the
scanner does not get a response in this time, it issues an error indication and discards the data. There are no
retries when a time-out occurs.
ACK/NAK
ENQ
When this option is selected, the scanner waits for an ENQ character from the host before transmitting data. If an
ENQ is not received within the Host Serial Response Time-out, the scanner issues an error indication and discards
the data. The host must transmit an ENQ character at least every Host Serial Response Time-out to prevent
transmission errors.
ENQ