We have a user with a 7975 IP phone. She has one DN configured at the first button and one DN at the last button. There are six buttons in the middle with nothing. She is able to get up to four calls at the same time on the top DN but not more. When the fifth call comes in she can hear it beep in her handset but does not see it appear on the phone and therefore cannot answer it. How do I configure the phone so she can receive and answer more than four calls? Thank you!
If you are using CM you should check the directory number configuration on the bottom of the page where you have two numbers for busy trigger and max number of calls that is allowed for the directory number. You can change these within certain limits.
if its CME use Octo line configuration for the DN, and create CNF and restart the phones.
ephone-dn 3 octo-line
if it CUCM, on the line you have option to increase