Cary,

        You might have a look at part 68 of the FCC Rules at
http://hallikainen.com/FccRules  .  It deals with direct connection to
the public switched telephone network.  Also, various companies make Data
Access Arrangements (DAA) that take care of the line interface.
Companies that come to mind are Clare and Cermetek.

Harold


On Fri, 2 Jan 1998 09:49:56 -0500 Cary Smith <casmith@lynx.dac.neu.edu>
writes:
>Hi,
>   can anyone recommend any good books that explains how a telephone
>works from the household perspoective. I am building a answering
>machine
>but I need to know how the rings signal are sent, the voltage levels
>on
>the lines and how the voice data is sent.
>
>Cary Smith
>