We've been successfully monitoring security over the telephone network for over 40 years and now there is something else on the horizon. 21CN is a new IP network under construction by BT that will send your telephone call in packets of data to the receiving telephone. This will be rolled out over a number of years and may not affect your area immediately.

However we're informing our customers now as after testing it could be found to have an impact on data transmission to our CMC. This may be the time to consider IP signalling which has the added benefit of Dual Path Signalling to ensure your security signals are delivered if either link fails.

More information on 21CN can be found here BT's 21st Century Network