Analog modem emulator?

[Tony Duell]

> 
> I have seen something like that. It essentially simulates a telephone
> network. You would use it to test modems, for example, or to connect
> machines that had internal modems. I think I saw it being sold by Black Box.
> They are not the cheapest outfit in the world. It's like buying at the local
> convenience store. IIRC they were over five hundred dollars. 

I am surprised, but I have never seen a published schematic for such a 
unit, neither in a magaxine or on the web. They can't be _that_ 
complicated, surely?

-tony