This may seem to be a wierd question. We have a user who got upgraded from a 7940 Ip phone to a 7970 IP phone. The new phone is setup from scratch.
The good news is that everything works absolutely fine. However, the user cannot increase the brightness on the phone. I thought that this could possibly be the problem with the phone and I replaced the IP phone whith another 7970 phone. The result sohow seems to be the same. Can anyone please tell me what is going on. Thanks in advance.
This is a very good question! This is likely a PoE issue.
Have a look at the following, which details numerous PoE setups where the IP Phone will only be Half-brightness
Table 2-2 Power Consumption and Display Brightness for Power Configurations
Phone Screen Brightness Approx. 1/2
Hope this helps!