A ringtone is read as a call for attention that is unmistakably yours. Hearing it in a dream stands for being summoned, or for a part of you asking to be answered.
Does the traditional reading fit your dream, or did it mean something else to you?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.