I'm looking for a Music-on-Hold Device that is bi-directional.

Here is the reason: I need to transfer audio content directly from my
digital telephone onto my Mac computer. Note that my telephone has an answering machine built into it, but I don't have the PBX system.

So I'm using the Music-on-Hold box as a way to do the transfer. Once on my computer, I'll work with the audio content as an mp3 file.

I've been looking at the OHP 6500 Music-on-Hold unit, but I'm not sure if it's bi-directional or not.

Thanks for any tips.