How do you set apart number groups in a phone number? In content on this site I've usually said it's up to the designer (or client).
"Using parentheses, hyphens, periods, spaces, or other characters to separate numbers in a phone number are generally a matter of preference and custom but be consistent in whatever method is chosen." (From my article on Parts of a Business Card)
In a recent blog comment Inked54 inquired about this:
"Question regarding use of dots in phone numbers - I know that this originated in Europe where there's lots of international calls. And it is becoming big in the US because most areas are a 10-digit dialing area. WE are not a 10 digit area - meaning we do not need to use the area code to make a call. When I see the 999.999.9999 to me that means I have to use all digits - when I see (999) 999-9999 means I don't - what is correct or is there a correct?"
I honestly had never heard that the formatting of the phone number was an indication that you needed to use the area code for dialing. For me, an area code was just an indication of where the number originated. If I wasn't in the same area code I knew I had to use it to dial the number. If I was in the same area code, well it may or may not be needed. If dialing didn't work without it, I'd add it in. My eldest daughter is working on her resumé and just the other day she asked if it was OK to use dots in the phone number. She just liked the way it looked. I said sure.
Is there an etiquette or preferred use that I wasn't aware of? Let me know what you know or think about this.