There could be a number of reasons:
If you hear a stuttered dial tone you might have a voicemail message. Dial 1571 from your business landline phone to hear it. Once you’ve listened to it and saved or deleted it, the stuttered dial tone should disappear
If you don’t have voicemail but still get a stuttered dial tone, take a look at the Business Phone user guide [PDF: 387KB] for all the features available and check your settings
If you’re hearing any other noise (like a crackling line), check the wiring around your business phone sockets and extensions in case any of it has come loose. We also recommend swapping the phone for a different one to check if that’s where the fault lies
If the problems continue, get in touch
Check the Vodafone Business Phone User Guide [PDF: 387KB] for more information.