^RT - Read RFID Tag
Reads tag data into a field or back to the host.
^RT reads tag data into a field number, so a format can print it on the label
or return it to the host with ^HV. It is a legacy command: the guide keeps it
only for formats written for older Zebra RFID printers, and current firmware
expects ^RF with the R operation. Read its parameter table anyway, because the
two commands number their blocks the same way.
Syntax
^RT#,b,n,f,r,m,sSupport
Accepted and skipped, because it configures the printer rather than the label. It cannot change the rendered output, and Labelary skips it too.
Reads the transponder. None exists, so a field that would receive the data stays empty rather than wrong. The renderer does not parse this command. It reports IGNORED_COMMAND at info severity, which does not reach X-Warnings. Labelary does not implement it either, so neither engine returns tag data. ^RF with the R operation is the current replacement for it. — not pinned by a test
Labelary does not implement it either, so there is no parity reference.
Parameters
#Field numberoptional · integerThe ^FN number that receives the data read, so a field on the label or an ^HV can print it. An ^HV with the same number returns it to the host as well.
- Default
- 0
- Accepted range
- 0 to 9999
- Invalid value
- not documented, and we have not measured it. The renderer does not parse this command or validate its arguments. The guide does not state what a printer does with an out-of-range value.
- Test coverage
- No test at the minimum, maximum or one step outside the range.
bStarting block numberoptional · integerThe first block to read. The maximum is the number of blocks the tag has.
- Default
- 0
- Accepted range
- 0 to the tag's block count
- Invalid value
- not documented, and we have not measured it. The renderer does not parse this command or validate its arguments. The guide does not state what a printer does with an out-of-range value.
- Test coverage
- No test at the minimum, maximum or one step outside the range.
nNumber of blocks to readoptional · integerHow many blocks to read, counting from the starting block. The maximum is the tag's block count less the starting block.
- Default
- 1
- Accepted range
- 1 to the tag's remaining blocks
- Invalid value
- not documented, and we have not measured it. The renderer does not parse this command or validate its arguments. The guide does not state what a printer does with an out-of-range value.
- Test coverage
- No test at the minimum, maximum or one step outside the range.
fFormatoptional · one of a setHow the printer interprets the tag data.
- Default
- 0
- Invalid value
- not documented, and we have not measured it. The renderer does not parse this command or validate its arguments. The guide does not state what a printer does with an out-of-range value.
- Test coverage
- No documented value is exercised by a test (0, 1).
0- ASCII. (default)
1- Hexadecimal.
rNumber of retriesoptional · integerHow many times the printer retries the operation on a single tag before it stops.
- Default
- 0
- Accepted range
- 0 to 10
- Invalid value
- not documented, and we have not measured it. The renderer does not parse this command or validate its arguments. The guide does not state what a printer does with an out-of-range value.
- Test coverage
- No test at the minimum, maximum or one step outside the range.
mMotionoptional · one of a setWhether the media feeds once the operation completes.
- Default
- 0
- Invalid value
- not documented, and we have not measured it. The renderer does not parse this command or validate its arguments. The guide does not state what a printer does with an out-of-range value.
- Test coverage
- No documented value is exercised by a test (0, 1).
0- Feed the label after the operation. (default)
1- No feed. Other commands in the format can still cause one.
sSpecial modeoptional · textA printer-specific flag with two unrelated meanings in the guide. On the R4Mplus with US firmware it decides whether the printer reads a block with a mismatched checksum anyway. On the R110Xi HF and R2844-Z it selects byte order. 0 is the default in both readings.
- Default
- 0
- Invalid value
- not documented, and we have not measured it. The renderer does not parse this command or validate its arguments. The guide does not state what a printer does with an out-of-range value.
- Test coverage
Behavior
The block count n is relative to the starting block and not absolute: on an
eight-block tag starting at block 6, n can only be 2. Several ^RT commands
can appear in one format, each filling a different ^FN.
The special-mode parameter is the awkward one. The guide gives it two unrelated meanings on two printer families: mismatched-checksum handling on one, and byte order on the other.
The renderer reads nothing, so every field an ^RT feeds prints empty. One
consequence matters for a page count. A format whose only content comes from a tag
draws nothing at all. Labelary returns no page for a format that draws nothing,
where this service returns one blank page.
Tested behavior
Example
The guide's example, with a caption added so the label is not blank:
^XA
^FO50,50^A0N,40,40^FDTag data^FS
^FO50,110^A0N,40,40^FN1^FS
^RT1,,,,5^FS
^HV1,,Tag Data:^FS
^XZ
Related commands
^RFRead or Write RFID FormatReads a tag, encodes a tag, or declares the access password used by later lock commands.^RIRead RFID Tag IDReads a tag's unique factory identifier and returns it to the host or to a field.^RURead Unique RFID Chip SerializationBuilds a 38-bit serial number from the tag's factory identifier for use in EPC data and in printed fields.