Component for working with Telephone line & modem

[ZarrinPour]

Hi all,
Is there any component (preferably free) for work with telephone line .i want to get notified when my telephone line is BUSY or RINGING or....and in general all states of a telephone line that is attached to my modem.

Any advise appreciated.

[Kambiz]

The TurboPower's award-winning Asyn Professional is now available freeware with source code.

Personally I don't suggest Async Professional for phone automation. When Async Professional was not freeware, my employer company bought it and we couldn't use it for our telephony application.

Async Professional is good (because of no other alternative) for writing fax receiver/transmitter programs, but for telephony applications (specially for interactive voice) it sucks.

The other alternative for Telephony is ExceleTel TeleTools, which is much better than Async Professional. Unfortunately this one is not freeware.