My staff and me are paid no standby rate for being on call but do get 1.5x hour for calls we actually work on. This is paid in 30min blocks so a 5 min call pays 75% of an hours pay. All staff do 1 week on primary call and 1 week on backup. They organise themselves if they need to go out and put on diverts. Does not limit social lives too much and they are rewarded for actual work done.