Etiquette and Class are learned. There is a lesson that absolutely MUST be taught: "How early is TOO EARLY to call?" No, I do not mean early as in after a date, I mean too early in the Morning! There are times of the day that are inappropriate to make a call.
There are two types of phone calls that we are talking about:
Personal Calls & Professional Calls
As far as I am concerned there is never a reason to call somebody before 9 am on your personal friendship list.
I am just having my second cup of coffee and trying to get my mind right at 8:30 am. This rule of course does not include the short list of Mama, Man or BFF.
*Mothers have a wonderful knack for calling you when you are getting those last 15 minutes of REM sleep.*
But everybody else is severely overstepping their boundaries if they call at even 8:59 am.
I do NOT receive professional phone calls before 9 am under any circumstances and I advise people in business to do the same. When you start taking "emergency" calls because you just had to, you will start receiving calls as early as your CEO opens her eyes. No can do.
However, there are the pesky "in the middle" type of people who you have generally professional relationships with BUT you all have each other's personal mobile phone numbers. Use your Do not Disturb Settings on your phone and handle that call at 9 am so that you can be completely caffeinated when you chat up the folks in your life both personal and professional.
All that I have to say on this matter is that it is not classy to answer your phone at 6:20 am in the morning (probably on your day off) with a frog in your throat.
As a side note, I also do not take professional calls after 8 pm nor to I take personal calls from a gentleman caller after 11 pm...
Boundaries are okay. Set some.