Table of Contents
Advertisement
RS-232 Parameter Defaults
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: Select this to transmit data immediately. The scanner expects no response from
the host.
• ACK/NAK: If you select this option, after transmitting data, the scanner expects either
an ACK or NAK response from the host. When it receives a NAK, the scanner transmits
the same data again and waits for either an ACK or NAK. After three unsuccessful
attempts to send data after receiving NAKs, 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.
• ENQ: If you select this option, the scanner waits for an ENQ character from the host
before transmitting data. If it does not receive an ENQ 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.
• ACK/NAK with ENQ: This combines the two previous options. For re-transmissions of
data, due to a NAK from the host, an additional ENQ is not required.
• XON/XOFF: An XOFF character turns the scanner transmission off until the scanner
receives an XON character. There are two situations for XON/XOFF:
• The scanner receives an XOFF before has data to send. When the scanner has data
to send, it waits up to Host Serial Response Time-out for an XON character before
transmission. If it does not receive the XON within this time, the scanner issues an
error indication and discards the data.
• The scanner receives an XOFF during a transmission. Data transmission then stops
after sending the current byte. When the scanner receives an XON character, it sends
the rest of the data message. The scanner waits indefinitely for the XON.
8-14
HS-360X Handheld DPM Scanner User Manual
Advertisement
Table of Contents
