Where can I find a download of the JTAPI implementation?
I am getting the following error: JSpeakerPhone.java:6: package javax.telephony does not exist import javax.telephony.*;
You have to find an implementation for whatever telephony solution you are using. JTAPI is just a specification much like JDBC, you need a specific driver for whatever solution you are using. There is a JTAPI implementation for ASTERIX for example.
Here is the reference implementation spec for JTAPI 1.4.
There is also gjtapi which might be useful for prototyping.