Let's be clear about what you are asking. If you are asking about paging tones such as those found around 152 mhz in many areas of the country, this is technically illegal per federal law. However, that being said, many do it, and don't talk about it. You would need a discriminator tap from your scanner to feed an appropriate application. Our wiki has numerous links that document precisely where to find a tap point, and how to do it. You do need some soldering experience, and some experience with simple hand tools to accomplish it.
However if you are referring to Fire Tone Outs, our wiki (and the West Pa. wiki) has quite a bit of information on this subject. At the bottom of the link below (in blue) is a link to a PDF file that describes the procedure using Audacity
Read the links and article referred to in the last message. Much will become clear to you. You don't need any special plug in, nor do you need any particular scanner. If you know the frequency the tones are sent on, you're half way home.
You should be a bit careful about referring to 'pager tones'; it's somewhat misleading, because someone might think you were trying to after a POCSAG type signal, and that's not true in this case. Saying 'toneouts' is far less confusing. 73 Mike