[Pritch]

It's quite rare for more than one person to be affected by noisy transmission, as it tends to be an issue on the copper part of the network. Keep an eye on this, I wouldn't be surprised if it flared up again. If it does, try getting a report on the line quality from someone who has called you. Put the phone down on them, and see how noisy the line sounds to them with the phone on the hook. If it goes silent when it's on hook, then it's probably a dodgy phone. If it stays noisy, or (as is often the case) gets worse, then there's an issue with your line.