Interesting. As a contra data point, I grew up in Sydney with 86 2050 as our landline (as if there were any other types of line! :) and I never saw hyphens use

Interesting. As a contra data point, I grew up in Sydney with 86 2050 as our landline (as if there were any other types of line! :) and I never saw hyphens used within phone numbers. I worked for Telstra during most of the 1990's, and didn't see it in use there either. Might be a regional thing? I note that our North American cousins enjoy splattering hyphens through their phone numbers. I like the space approach.