Symbol Technologies DS 3408 - Manual (Page 231)

Miscellaneous Scanner Options 14-9
Transmit “No Read” Message
Parameter # 5Eh
Scan a bar code below to select whether or not to transmit a No Read message. When enabled, the characters NR are transmitted
when a bar code is not decoded. When disabled, if a symbol does not decode, nothing is sent to the host.
Enable No Read
(01h)
*
Disable No Read
(00h)