“21CN is BT’s global, software-driven customer network that introduces new next generation services” – http://btplc.com/21CN/
Over the next few years, BT will be migrating all their telephone exchanges to the new 21CN (twenty-first century network) platform. To ensure that end users will face as little disruption as possible, BT have performed various tests on equipment those users are likely to have installed at their premises.
Of the equipment tested, only one was found to be incompatible – a BT telephone system called ‘Monarch’. If you or anybody you know has a Monarch installed, you will need to change it before your exchange is converted.
BTs tests also uncovered various problems with echo being introduced into conversations where analogue equipment was being used. We recommend that all businesses using analogue lines for their communications migrate to ISDN or VoIP whereever practical.
If any of these issues affect you, please don’t hesitate to conatct us.