What is the effect of installing ADSL on my alarm line? Print this page   Most alarm systems will operate as normal, but some which use 'out of band' (greater than 4khz) signalling will be incompatible. To check whether your alarm system is compatible please refer to your alarm system manual or provider. Red Line and Red Alert are known incompatibilities.   Is this enough information? Great! Click this button to go back Ok, click this button to contact us   Back to previous page