I have had this phone since February 2021 and it has worked fine since, but recently (December 2021) occasionally my BT 2600 Decor phone displays 'No Number' instead of recognising the number of some friends who are saved on the phone and asks them to say their name, as if their number is not on the saved list.
Possibly a failure of the CLI signal coming in on your phone line. Who provided your phone service?
Thanks for your reply, however, it works OK most of the time. During last week one of my friends called on Monday and it worked, but then Thursday it did not and then it didn't work again for him on Saturday. A second friend called last week when it worked OK, but today when he called it did not work. I have only had the problem with two friends so far, but the problem seems to be intermittent. My other 'non-blocking' phone shows the number OK every time.
I am with BT and have the CLI service activated in my account.
Its possible that a line fault is causing the CLI tone burst to be low level. This is sent just before the first ring,
It could also be a fault on the exchange line card which is sending out an intermittent weak signal. Having other phones plugged into your line can also reduce the signal level.
You could try running a line test to see if a fault is indicated. Actually, the very act of running a line test activates a number of mechanical relays in both the line card, and the line test system in the exchange. And this can sometimes fix the problem, as it breaks down any oxidisation on the relay contacts.
I an assuming that you are not on BT Digital Voice?