You could use something like a MAX232 RS232 converter if you really needed... but a lot of times... a resistor with a 5.1V Zener to ground works too. (or a diode to +5 works... with an input diode that blocks the -12VDC.)

don't really need an IC to do it.
_________________________
Empeg Mk2 in fabulous green! Green Face, Green BackLit Buttons... GREEN...