Any idea how this is done ?

there is an IVRS based application , and in that ,caller id information is a must . they(client) say that they need the caller id information even if it is blocked , and companies like **broken link removed** have this ability .
AFAIK, the CLIP info is send by the telecom company , then how can be the above statment be true?

In Australia some organisations, such as government and emergeny services, have the ability to view caller ID information even if it is blocked. I assume this would also be the case in other countries.
The likely hood of a telecomunications company selling a device that can read blocked caller ID information to civillians is extremely remote.

thanks 'suicidalmonkey' . but my question is , it is the telecom company who blocks/unblocks the facility , and by adding an 'instrument' how can we overcome it?.
as far as i understand , to emergency/govt: lines clip is not blocked,eventhough the party requested not to reveal his id. right?

akg said:

thanks 'suicidalmonkey' . but my question is , it is the telecom company who blocks/unblocks the facility , and by adding an 'instrument' how can we overcome it?.
as far as i understand , to emergency/govt: lines clip is not blocked,eventhough the party requested not to reveal his id. right?

Click to expand...

As already explained, you can't add something - the Police merely request the details from the telecoms company, they still have the caller ID logged, it's just not sent on to the public.