Revelation is communication from God. And scripture is communication from God. This means that the writers of the scriptures were inspired by God through the Holy Ghost. If we accept the Bible as the word of God, we accept the idea that, when men are inspired to write God's word, this inspiration is, indeed, communication from God. God communicates his word or His Will to the mind of an inspired man, who, in turn, writes it.
Revelation can take many forms.
There are visions as John had on the isle of Patmos. The old Testament refers to a remarkable instrument, known as the Urim and Thummim, by which the ancient seers communicated with God. God reveals or communicates His will every time he heals the sick or performs any kind of miracle. All of these forms of revelation are forms of communication from God. Hence, it would be proper to say that all revelation is communication from God.