Hey,
In my rural Ohio hospital (Level III Trauma), all Surgery RN's take call.
At one time there were 7 of us!
That translates out to 1 in 7 weekend, and a rotation during the week.
Right now, due to vacations, illness, vacancies, etc, there is about 3 of us taking call.
So you can do the math.
The thing that I've found about call, and at least our surgical "world", that all things tend to even out. One night or weekend, you'll get pounded, another, you keep checking the phone/beeper to see if they work!!!
Sorry, can't tell you what others do. I know many have additional shifts, etc.
Ours is basicly 7-3:30 Monday thru Friday.
Call starts at 3:30 pm til 7 am weekdays, 0700 Saturday, thru 0700 Monday for the weekends. That's where I'm at right now, fearing the phone!!
Hope that helps
Mike