DTMF tones input on the PC audio card can be used for playback control:

Open Settings menu > Modules > Remote tab.

Select the DTMF Input plug-in and enable it.

Press Configure to specify the audio device for receiving the DTMF tones and the command to be executed at receiving certain DTMF sequence.

Click on the white sheet button to add each command to the list.

Click OK to apply.