I have normal landline. I am going to release next version of that with the following facilities.

i) Caller ID
ii) Caller Display (We should be able to see the person talking to us in the display. this could be achevied by attaching a web cam to the phone)

I just wanted to know different testcases to test new version of my phone with the above facilities.....

Hi,

I can share what i know about this domain.

Before writing test cases you need to look for physical and logical scenario for landline technology

Physical Scenario
a) Find the focus of webcam
b) if the phone is cordless how should it reach the caller
c) Display of caller ID
d) Display Light illumination

Logical Scenario

a) Try to find the communication details on phone like how far this should work does it cover the international call ,national call.....
b) The communnication port between each node (end to end communication) need to be traced out
c) Timer set for the caller

These are basic requirements please find more from the people who have communication in Electronics

Cheers,
Sridevichitthu