Microsoft’s James O’Neill has been on a crusade for a while now, trying to educate the world (well, the UK at least), that numbers written in the format +44 (0) 1234 567890 are wrong and that the E.164 format should be used instead. Of course, James is right (he explains more in a recent blog post and Ewan Dalton illustrates the issue a little more clearly in his post on the subject) but so many numbers are written incorrectly – it’s not uncommon to see 0207 xxx xxxx (the area code is 020 and the 7 is part of the local number) – and advertising only national rate numbers (as Microsoft does on it’s UK contact page) is not good practice either (another campaign related to phone numbers is Say No to 0870).

What I found particularly interesting is James’ explanation of making a phone number appear as a link in the form of tel:+44-1234-567890 so that those with a supported dialler (like Microsoft Office Communicator) can click to dial (for further information, see RFC 3966). I’ve updated my e-mail signature now (even if it does break the corporate rules for signature formatting)… unfortunately Outlook 2003 keeps on removing the link!