Using Caller Line Identity Display - CLIP?

Asking all you technical geniuses out there for a sensible answer please. I have a new Fax/Answerphone and have Caller Line Identity Display facility on it. Instruction booklets on anything technical these days seem a foreign language to me so can anyone explain what I need to do in order to get this facility up and running. I have enquired of my telephone company to connect this for me and they have said that this has been done. However when I get a call the display still says UNKNOWN even though I know that the number is not a 'withheld' number or an 'ex-directory' number. Is there something else I should be doing or is it the fault of my telephone provider. Incidentally the telephone provider is Talktalk and we have had lots of trouble in the past firstly getting Broadband up and running and then getting the Fax working. Help!!!!!!

Sorry to Phat Baz and all those who agree with him, I have got a friend to ring me, whose name is in my address book and it still comes up UNKNOWN. I know I'm not technically very clever, but I wouldn't have posted a question without testing this first, so lets have someone with some real knowledge!!!!

there are really only 2 issues with CID services, either your equiptment, or it has not been programed in the switch properly...

you should take another phone with caller ID and connect it to the fax jack, and call the number with an unblocked call to see if the CID info comes up... if it still displays unknown then you need to call your phone company to resolve the issue on there end in the office...

another test that you can perform is to connect the fax line to one of your voice lines, and ring that number and see if the number still comes up unknown...

be sure that the number you are calling from is unblocked, when in doubt dial *82 before dialing to unblock the number..

if the above tests show that CID is working on the fax line, and CID info is not comming thru the fax machine, even on the other number, then more then likely there is a defect within the fax machine, because the CID info should be displayed for each call with out the need to set it up...

When it come up unknown it means that particular no is not in your phones internal directory or the only other reason is someone is on an extension in an office and ringing you or they are witholding the number.
Baz

unless you have put the number in your telephone directory it will not show.it only shows numbers you have put into it.

Yep. Phat Baz has got it right. You must remember, the caller has to be in your internal directory otherwise it won't recognise the number. A simple way to test this is to put your mobile number into your phone directory and then ring it from your mobile. If your name (or whatever you have put into your mobile) doesn't come up then there's something wrong with your phone/fax.

Also, as Phat Baz has said, people can withold their number by dialling '141' before the number they wish to dial. This will withold the number, even if their number is in your internal directory.