"so please tell me what r all pre-requisite to enjoy the facility of Caller ID through modem"
Call Waiting in addition to Caller ID.
Even without Call Waiting you should see the message of an incoming call, on the PC, along with the ID, when you are not on the internet?
Have a friend call you while you are not connected to the internet to test it.
Beyond the above information, in order to converse using the PC's modem the setup has to be Full Duplex. Without looking into it I don't know what controls the fact of being full duplex or not (sound card, modem or OS?).
If it is not full duplex then you can actually talk with someone but you have to use it like a two way radio (walkie talkie) where only one person can talk at a time.
To test for Full Duplex open up two instances of Sound Recorder.
Start, Programs, Accessories, Entertainment, Sound Recorder.
Using the first instance record anything by microphone or by line for about 5-10 seconds worth of it.
Once done, hit the Play button and then hit the record button on the second instance of Sound Recorder to see if it will record the sound at the same time that it is playing the sound on the first instance.
When done, hit the Play button on the second one to see if it recorded. If it did then you have full duplex.
Regards,
Bryan
