Why is there no tax being charged on the register (PCRT500/520/2300/2400 SE-S400/800/900/3000/3500)

This could be caused by any of the following:

1. Tax rate (in PGM mode > Tax Setting > Rate) is set to 0.
   Set the appropriate tax rate.
2. Calculation type (in PGM mode > Tax Setting > Cal Type) is set to "NON".
   Most users should set this to "ADD ON". (If you want to enter prices that already have tax included, and back calculate the tax later, then you can set this to "ADD IN" instead.)
3. Taxable status of department/PLU (in PGM mode > DEPT Setting) is set to "NON TAX".
   Select the appropriate taxable status ("T/S1" for taxable status 1, "T/S2" for taxable status 2, etc.).

Please see the following document for more information on adjusting these settings:

https://casiosupport.zendesk.com/hc/en-us/articles/8064464085657-Tax-table-programming-for-menu-driven-entry-level-cash-registers