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Device onlyprinterdevicesession scope
^JT

Head Test Interval

^JT configures head Test Interval. It applies to the printer session and subsequent formats and controls printer hardware or connectivity rather than label pixels.

ZPLr compatibility note

  • Recognized by the renderer but has no label-raster effect.

These are code examples only. This printer or session command does not produce a standalone label image.

Syntax
^JT####,a,b,c
####

Four-digit number of labels printed between head tests

Sets four-digit number of labels printed between head tests. It can be omitted when the documented default is suitable.

Default
0000 (off)
Range
0–9999
Required
No
Documented values00009999

#### variations

Compare values side by side; other parameters remain at representative defaults.

Side-by-side comparison2 variations

#### = 0000

Uses 0000 for four-digit number of labels printed between head tests while the other command values stay at representative defaults.

Edit in editor
ZPLcaret-jt-value-1.zpl
^JT0000,N,0,9999

#### = 9999

Uses 9999 for four-digit number of labels printed between head tests while the other command values stay at representative defaults.

Edit in editor
ZPLcaret-jt-value-2.zpl
^JT9999,N,0,9999
a

Manually select range of elements to test

Sets manually select range of elements to test. It can be omitted when the documented default is suitable.

Required
No
Documented valuesNY

a variations

Compare values side by side; other parameters remain at representative defaults.

Side-by-side comparison2 variations

a = N

Uses N for manually select range of elements to test while the other command values stay at representative defaults.

Edit in editor
ZPLcaret-jt-a-1.zpl
^JT0000,N,0,9999

a = Y

Uses Y for manually select range of elements to test while the other command values stay at representative defaults.

Edit in editor
ZPLcaret-jt-a-2.zpl
^JT0000,Y,0,9999
b

First element to check when parameter a is Y

Sets first element to check when parameter a is Y. It can be omitted when the documented default is suitable.

Range
0–9999
Required
No
Documented values09999

b variations

Compare values side by side; other parameters remain at representative defaults.

Side-by-side comparison2 variations

b = 0

Uses 0 for first element to check when parameter a is Y while the other command values stay at representative defaults.

Edit in editor
ZPLcaret-jt-b-1.zpl
^JT0000,N,0,9999

b = 9999

Uses 9999 for first element to check when parameter a is Y while the other command values stay at representative defaults.

Edit in editor
ZPLcaret-jt-b-2.zpl
^JT0000,N,9999,9999
c

Last element to check when parameter a is Y

Sets last element to check when parameter a is Y. It can be omitted when the documented default is suitable.

Range
0–9999
Required
No
Documented values99990

c variations

Compare values side by side; other parameters remain at representative defaults.

Side-by-side comparison2 variations

c = 9999

Uses 9999 for last element to check when parameter a is Y while the other command values stay at representative defaults.

Edit in editor
ZPLcaret-jt-c-1.zpl
^JT0000,N,0,9999

c = 0

Uses 0 for last element to check when parameter a is Y while the other command values stay at representative defaults.

Edit in editor
ZPLcaret-jt-c-2.zpl
^JT0000,N,0,0

Primary source

Official Zebra reference

Use the manufacturer reference for printer- and firmware-specific behavior beyond ZPLr’s pinned rendering profile.

Open Zebra documentation