A: The Tier 2 plan of Noysi, also known as the Unlimited plan, is the only one that includes a custom CNAME. This means you can use your own subdomain to access Noysi, instead of using Noysi's default subdomain.

For example, instead of "yourcompany.noysi.com", you could use something like "chat.yourcompany.com".

This custom CNAME feature is the main difference that distinguishes the Tier 2 (Unlimited) plan from other plans. There isn't a separate "Noysi Unlimited" plan in addition to Tier 2 - they are the same plan.

If you need more details about the specific features of the Tier 2 plan or want clarification on any other aspect, please feel free to ask.