Many of the Future Kit telephone add-on device and accessories are not available from regular telephone equipment vendors. Those that do stock them often ask an unreasonable premium for them. Hobbyists who adapt these easily constructed projects will increase the amenity of their phone system and save money at the same time. Students building these projects will be introduced to the fundamentals of the telephone system as well as deriving a practial and useful outcome. These units are available also as pre-assemblies under the FA prefix.