Star StarPRNT SM-L Series Command Specifications page 101

When s = 3, and s = 4 (Document start command + document end command), printer operates as though in data cancel mode.
If there is an error after receiving the document start command, reception data is received and discarded until the document
end command is received when the printer is recovered from the error.
If the document end command cannot be recognized, all reception data is destroyed. (data intake mode)
Timeouts are 10 seconds. Automatically cancels the data intake mode.
Restrictions
1) Sleep mode decrease
2) Erroneous printing occurs if the same data as the End command is contained in the raster data or bit image data.
3) Invalid when in Page mode
When S=3 is specified, an initialization processing is executed as same as <ESC> "@".
The interface disconnection detection function through data reception timeout is controlled when s=5 is specified.
When this function is enabled, the interface is determined to have been disconnected when no data is received for a specified
period of time at the data read section of the printer.
When a disconnection is detected during a command execution, the command parsing is stopped.
n1=0 and n2=0: Initializes the interface disconnection detection function through data reception timeout.
(Returns to the MSW settings. The initial value for the timeout time is 3 seconds.)
n1=1 : Set enable/disable and the timeout time for data reception timeouts.
When n2 is 0, the disconnection detection function is disabled due to data reception timeouts.
When n2 is anything except for 0, the data reception timeout is set. (Units: seconds, 1 to 255 seconds)
n1=2 and n2=0: Sends the current setting to the host.
The data format returned to the host is as shown below.
<Returned Data Formats>
Code ASCII
Hex.
Decimal 27
* Echoes back the specified contents from the host as is until ESC GS ETX s n1 n2, and then sends the print end
counter value and NUL.
This function is invalid at the time of program rewriting.
Star PRNT Command Specifications
ESC GS ETX
1B 1D 03
29 3
s n1 n2 [timeout setting] NUL
s n1 n2 [timeout setting] 00
s n1 n2 [timeout setting] 0
2-87