2 phone Intercom circuit diagram which can be used upto 1km in outdoor using ringer

[ghaudesh]

I want to build a 2 phone intercom which can be used upto 1km using speaker of same phone to create ring on other side please help

 

[mister_rf]

See here similar project:


http://www.instructables.com/id/Old-Phone-Intercom-Device/

---------- Post added at 18:16 ---------- Previous post was at 18:12 ----------

http://www.diy-electronic-projects.com/p313-High-Quality-Intercom

http://www.afiata.com/full-duplex-intercom-pcb-for-your-office-and-house/

 

[kene.dozie]

Does any one know how to design a door video intercom?