Reference:
https://downloads.avaya.com/css/P8/documents/101005087 Page: 9

Examine the IP Telephone VoIP settings: Review the configuration of the IP Telephones to ensure there are no issues with codecs or other VoIP settings that could cause delays in call quality.
Enable RTCP monitoring: RTCP (Real-time Transport Control Protocol) can be used to monitor call quality metrics such as jitter, packet loss, and delay. Enabling this monitoring can help pinpoint the source of the lag.

It can be upgraded to the Select version: The Avaya IP Office Server Edition (non-Select) can be upgraded to the Select version, offering additional features and scalability options.
It is a software-based solution: The Server Edition is a software-based solution that runs on a server platform, as opposed to hardware-based systems.
It can be expanded to support 2,000 users in non-Select: The non-Select version of the Server Edition can support up to 2,000 users, making it suitable for medium to large deployments.

Administrator Password: This is the password used to access the administrative functions of the system.
Security Password: This password is used for security-related settings within the system.
System Password: This password is required to access and manage the system's configuration.