Paxar Monarch 9850 - Manual (Page 176)

I n q u i r y R e q u e s t ( E N Q )
An ENQ character acts as a request for printer status information.
You can send an ENQ in front of, in the middle of, or immediately
following any packet downloaded to the printer. An ENQ is a
command that can be executed as part of a packet or sent on its
own (using a communications program). An ENQ is processed
immediately. The ENQ character is user defined.
The ENQ character does not appear as a
visible character; however, we are
representing the
ENQ character as E .
I n q u i r y R e s p o n s e
Printer status is returned to the host in a 3-byte (3-character)
sequence. The first byte is the non-printable user-defined ENQ
character, which is not visible on the response. The second and
third bytes are printer status codes. See the ENQ Reference
Tables for the meaning of bytes 2 and 3.
Example: E AB
The status codes (A and B in this case) are ASCII equivalents to
the hexadecimal bits that represent the various types of status
responses. This response indicates that the printer is online
(Character A) and that there is a stock fault (Character B).
Example: E
??
Indicates that this is the first ENQ response since the printer was
turned on. Send another ENQ immediately to receive the printer’s
status.
Example: E @@
Indicates the printer is offline.
7-2 Status Polling