Physicians "round" on their patients once or twice daily, alone or as part of a team that may include an attending, residents, med students, PAs, etc., to review the charted notes, diagnostic tests, reassess the patient, and tweak the treatment plan if needed. If they are part of a teaching service, then each patient becomes a teaching opportunity, presented in detail by whichever team member has primary responsibility for them.
"On call" means that one must be available to admit or manage patients, by phone, pager, or with one's physical presence. This implies after-hours responsibility which may be evenings, overnight, or on weekends.