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.

7-2Status Polling

Page 152
Image 152
Paxar 9403 Q u i r y R e q u e s t E N Q, Q u i r y R e s p o n s e, Indicates the printer is offline 2Status Polling