^JU - Configuration Update
Saves the printer's current settings to non-volatile memory, or reloads saved or factory settings.
^JU makes a printer's current settings its settings after the next power cycle.
Most configuration commands — ^SC, ^KL, ^MP and the rest — change the
running configuration only. ^JUS commits it to non-volatile memory, and ^JUR
and ^JUF return it to the last saved state or to the factory one.
Syntax
^JUaSupport
Accepted and skipped, because it configures the printer rather than the label. It cannot change the rendered output, and Labelary skips it too.
Nothing persists between requests, so no stored configuration exists to save or restore. Every render begins at printer defaults. The renderer does not parse this command. It reports IGNORED_COMMAND at info severity, which does not reach X-Warnings. Labelary is also silent, so the rendered label is identical in both engines. — not pinned by a test
Labelary renders this command.
Parameters
aActionrequired · one of a setWhich configuration operation to perform. All of them act on persisted printer settings, not on the format.
- Invalid value
- not documented, and we have not measured it. The renderer does not parse or measure this command. The guide states only that a value is required.
- Test coverage
- No documented value is exercised by a test (S, R, F, N).
S- Save the current settings, which the printer then uses at power-on
R- Recall the last saved settings
F- Reload factory settings, which do not survive power-off unless
^JUSfollows N- Reload factory network settings
Behavior
The distinction matters for ^JUF. The guide notes that the printer loses factory
values at power-off unless a ^JUS follows. A permanent reset therefore takes two
commands, not one.
Nothing persists between requests: every render starts from the printer defaults, whatever the previous one contained. No stored configuration exists to save, recall or discard, so the renderer ignores this command.
Differences from the specification
Labelary against the ZPL II guide
Where Labelary — our compatibility target — behaves differently from the printed specification.
- Labelary accepts a fourth value,
N(reload factory network settings). The 2006 guide documents onlyF,RandS, soNis a later addition. — not pinned by a test
Example
The current configuration saved. Sent to a printer this would make the surrounding settings permanent; here the label prints unchanged and nothing is carried into the next request:
^XA
^SC19200,8,N,1,X,A
^JUS
^FO50,50^A0N,40,40^FDConfig saved^FS
^XZ
Related commands
~JRPower On ResetResets the printer as though an operator power-cycled it.^JZReprint After ErrorControls whether the printer reprints a label that an error interrupted, after the error clears.^MPMode ProtectionDisables individual front-panel functions so an operator cannot change them.