What is the 25-Line SIP Account?

The 25-Line SIP Account is built for organisations that need to make and take many calls at once. It provides twenty-five concurrent SIP channels on a single account, so up to twenty-five conversations can run simultaneously across your team, your call centre or your PBX.

Everything is managed under one account and billed as a single flat monthly fee — there are no per-seat or per-extension licence charges. You can connect it to your on-premise or hosted PBX, or register individual handsets directly, and grow your telephony without re-architecting your setup.

You can read more on the product website: https://freevoip.co.uk/services.html