About 4 years ago I wrote a post about Sangoma Tapping with Asterisk. Many people has been interested in that and I’ve done a few implementations with it.
Having said that, still showed some stability issues and it became a burden to maintain because it is a patch to Asterisk.
Something you may find interesting is that a bit later after I wrote the tapping feature for Asterisk, I also did it for FreeSWITCH 🙂
It has been more stable in FreeSWITCH, mostly due to the fact that FreeSWITCH TDM abstraction is modular and it has been much more easy to maintain a tapping module rather than a patch. You can find the module in FreeSWITCH’s tree at libs/freetdm/src/ftmod/ftmod_pritap/ftmod_pritap.c
In addition to the TDM tapping module, I also wrote an RTP tapping module called mod_oreka that can be used for tapping any media stream on FreeSWITCH (SIP, TDM, H.323 etc)