[Asterisk-Users] Line sharing

[Christian Schnell]

Hi, I would like to have a VoIP-card share a physical phone line with 
some other analog device. When a call comes in it is supposed to be 
answered by that analog device, only occasionally I'd like the VoIP-card 
to "join" that conversation. Using the VoIP-card, I'd like to establish 
a three-way conference (external party, analog device, PC+IP-phone) and 
then also record that conversation digitally to a PC in the LAN. All 
three parties must be able to hear and speak freely.

You may wonder why such a complicated setup. The reason is that the 
"other analog device" is not a telephone and not a modem, it's a mix of 
both (a proprietary hardware). Normally it behaves like a modem, but 
given the correct command it switches to voice mode and behaves more 
like a telephone then. Voice is not digitized, the two modems are 
basically silent and passive while the line is used for analog voice 
conversation. A typical session looks like this:

   CONNECT --[ data ]--[ voice ]--[ data ]-- DISCONNECT

If I wouldn't share the physical phone line I'd be forced to pass the 
modem traffice through two VoIP-adapters, and this plus modem 
pass-through (through the IP network) doesn't seem to be a wise choice.

Intels Dialogic D160SCLSHIZ seems to be a possible hardware choice, but 
I wonder if I can use a say Digium or VoiceTronix card to accomplish the 
same. Intel offers a whole set of Line-Tapping Boards, is it possible to 
"tap" lines with other boards, too? Has anybody experiences with line 
tapping setups of this kind?

Thanks,
Christian.