Talking on the phone is a privilege, not a right. Whether teens are talking to boys or girls on the phone, the rules should be the same, so I am hoping you have set up the guidelines in a family meeting, or at the very least in a calm discussion with your daughter. Those guidelines should include:
1) The hours that your daughter can receive calls. e.g. not after dinner, not after 8:00;
2) Telling you the first and last name of who called if you ask;
3) Talking for a limited time -- 15-20 minutes or less; and
4) Privacy for your daughter but with you overseeing the conversation in case she appears upset or confused by the call.
Trust your daughter, but use common sense and your intuition about what kind of conversations are taking place. If you answer the phone and someone wishes to speak with your daughter, always ask who is calling; get the last name if you don't know the child. Hopefully you daughter will trust enough to ask for your help if a caller is out of line.