I am assuming that we are talking with respect to Communications Manager version 5.X and Later.
With this release Device License Unit concept was added which enforces phone license.
Now every phone consumes certain DLU (Device License Unit) which varies depending on the phone model.
For example 7940 will consume - 4 DLUs
7911 - 3 DLUs
So you purchase DLUs typically available in a pack of 10 whcih needs to be uploaded on teh CUCM. So lets say you have got 100 DLUs loaded on the CUCM. YOu add 5 numbers of 7940s. Eeach consumes 4 DLUs hence these 5 IP Phones will consume 20 DLUs.
On the CUCM as soon as these phones register from the pool of 100 DLUs 20 will be consumed and you'll be left with 80 DLUs which will be consumed by other devices.
For your reference I am attaching an excel sheet which gives you the number of DLUs required for various IP Phones models.
Are you getting this error “Installer User Interface Mode Not Supported. The installer cannot run in this UI mode. To specify the interface mode, use the -i command-line option, followed by the UI mode identifier. The value UI mode identifiers...
The below trick might come handy when you have to add a new node to a cluster but you don't have or is unsure of the security password for the publisher. This procedure has been around for ages.
1) Login into the CLI of the Publisher.