Inside the applications note described as st_ap19 and shown to be the Sept '96 issue of N&V it contains two items. This is about the second, how to connect the stamp to a phone line. The circuit described on page 2 of the PDF is credited to a particular book,
"Encyclopedia of Electronic Circuits, Volume 5, by Graf and Sheets (TAB/McGraw Hill, 1995; ISBN 0-07-011077-8)". Especially since the author mentions that DAA devices were expensive. And this was written about by Scott Edwards, by the way.
During that time period an outfit originally named CP Clare came out with a family of modules that basically compresses nearly all of that into an easy to work with package. They are now made by IXYS by the way. Anyway the part number is CYG2000. (For starters.)
And why am I bringing this up one of you might ask? Because I am wondering if during the interim anyone here has tried out the idea described in that note.