RS-232 input devices
MB/NX/RM/00/E/970131
115
ENQ / ACK / NAK software protocol
The RS-232 input device connected to the MicroBar NX can synchronize communication by
sending an ENQ character (05h). The MicroBar NX answers with an ACK character (06h)—
even if ENQ/ACK/NAK has not been activated in the MicroBar NX.
When a message—terminated with the selected end-of-message character—is received
from the RS-232 input device, the MicroBar NX sends an ACK character if the message is
understood, or a NAK character (15h) if the message is not understood. The ACK character
is sent when transmission has been completed.
The hardware/software protocols timeout for RS-232 input devices is unlimited and can not
be configured.
Typical ENQ / ACK / NAK scenarios
RS-232 input device
RS-232 input device
message
(not OK)
NAK
ENQ
ACK
(clears message)
repeats message
(OK)
ACK
ENQ
MicroBar NX
MicroBar NX
message
(OK)
ACK
(clears message)
ACK
Summary of Contents for MicroBar NX
Page 1: ...MB NX RM 00 E 970131 M i c r o B a r N X Reference Manual Preliminary Edition January 1997...
Page 10: ...Contents x Contents MB NX RM 00 E 970131...
Page 177: ...Symbologies EAN 128 MB NX RM 00 E 970131 167 Symbologies EAN 128 Symbologies Code 128 EAN 128...
Page 201: ...MB NX RM 00 E 970131 Number codes 1 2 3 4 5 6 7 8 9 0 End Selection...