Software Handshaking (Continued) - Symbol P370 Keyless Reference Manual

P370/P470 Keyless RF Scanners Product Reference Guide

Software Handshaking (Continued)

ACK/NAK
When this option is selected, after transmitting data, the cradle expects either an ACK,
Acknowledge, or NAK, Negative Acknowledge, response from the host. Whenever a NAK
is received, the cradle 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 cradle issues
an error indication and discards the data.
The cradle waits up to the programmable Host Serial Response Time-out to receive an
ACK or NAK. If the cradle 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 cradle waits for an ENQ, Enquiry, character from the host
before transmitting data. If an ENQ is not received within two seconds, the cradle issues an
error indication and discards the data. The host must transmit an ENQ character at least
every two seconds to prevent transmission errors.
ENQ
ACK/NAK with ENQ
This combines the two previous options.
ACK/NAK with ENQ
4-86