We have the need for a very simple internal phone system with no outside access needed and would like any input on the best and cheapest solution to accomplish the following:
Total of 4 phones in seperate rooms. When any of those phones are picked up they need to automatically call the operator (5th) phone. The operator phone needs to know which phone is calling and should be able to call any other the other phones. That's it- no phones need to call anything outside, in fact the 4 phones don't even need any buttons.
All suggestions are much appreciated!