Chord sequence
D♭m7 F♯7 Dm7 G7
In every key
Four-note rootless voicings in their two forms, with the 3rd or the 7th on the bottom, played over the root.
Heard in C major
Chords 1 to 2
Dbm7 F#7
Chords 3 to 4
Dm7 G7
Over Dbm7 · ♭ii7
Mode 6 of Blues
Over F#7 · V7/vii
Over Dm7 · ii7
Mode 2 of Major
Over G7 · V7
Mode 5 of Major