~JB - Reset Optional Memory
Reinitializes the B: drive, the operation a printer needs after its memory-card battery fails.
~JB reinitializes the B: drive. The guide gives it two jobs. A format
must send it after a replacement of the battery in a battery-backed memory
card, because the card cannot function until then. A format can also send it to
clear B: on purpose. Either way the card loses its contents. This is not the
^JB command with a different prefix. ^JB takes a device letter and formats
A:, B: or E:. ~JB takes no argument and only ever touches B:.
Syntax
~JBSupport
Every documented parameter renders the same output Labelary produces.
This command differs from ^JB and only shares the mnemonic: it takes no arguments. It is otherwise exactly ^JBB — it erases whatever device the letter B names, which ^CM can change. Text written after it is unrecognized content. Measured against Labelary on 2026-08-19. — not pinned by a test
Labelary renders this command.
Parameters
~JB takes no arguments.
Behavior
A failed battery shows as a battery-dead condition on the printer configuration
label, which ~WC prints. A replacement battery is not enough on its own:
without a ~JB afterwards the card stays unusable. A deliberate clear needs a
writable card, because the printer cannot reinitialize a write-protected one.
The scope is exactly B:. Labelary removed a graphic stored on B: and left
one stored on E: readable (measured 2026-08-19). After a ^CM remap, B:
means the device that now answers to that letter, which makes this command
exactly ^JBB.
It does not need a format around it: in the same measurement, a ~JB between
two formats cleared B: as one inside a format did. Text written after it is
not an argument and is reported as unrecognized content.
Differences from the specification
Example
Three formats in one request: store a graphic on B:, clear B:, then try to recall it:
^XA
~DGB:TEST.GRF,32,2,FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
^XZ
^XA
~JB
^XZ
^XA
^FO50,50^XGB:TEST.GRF,4,4^FS
^FO200,50^A0N,40,40^FDafter reset^FS
^XZ
Related commands
^JBInitialize Flash MemoryReformats one flash storage device, and discards every graphic, font and format stored on it.^CMChange Memory Letter DesignationReassigns the drive letters `B:`, `E:`, `R:` and `A:` to different physical storage devices.^IDImage DeleteDeletes a stored object from printer memory.~DGDownload GraphicDownloads an ASCII-hex bitmap into printer memory as a `.GRF` object.^XGRecall GraphicDraws a previously downloaded graphic, optionally magnified.