Use [`INT 21h/AX=6601h`](https://fd.lod.bz/rbil/interrup/dos_kernel/216601.html) to get the current code page information and then [`INT 21h/AX=6602h`](https://fd.lod.bz/rbil/interrup/dos_kernel/216602.html) to actually set the code page.
Use
INT 21h/AX=6601hto get the current code page information and thenINT 21h/AX=6602hto actually set the code page.