Look in the datasheet, of course. Under "electrical characteristics", you see:
[ref: +Vs]
Mute / Play Threshold: -7..-5V, -6V typ.
Stand-by / Mute Threshold: -3.5..-1.5, -2.5 typ.
A bit confusing, if you don't notice the [ref: +Vs] at the top of the section, but that is saying that the threshold voltage for mute/play is between 5 and 7 volts below V+, and for standby/mute, between 1.5 and 3.5 below V+. You should be able to directly apply those voltages to those pins. The circuits they give as examples just shift digital signals (0-5V) to those levels.