Multiple Schematic Wiring Diagram Split Receptacle. The bottom drawing shows how it is usually done. The first one shows the method with the neutral conductor in the switch box.
That will leave the black and blue wires in the 4 conductor to be the two travelers. A switch loop single pole switches light dimmer and a few choices for wiring a outlet switch combo device. The bottom drawing shows how it is usually done.
The source for the circuit is at the switch and 2 wire cable runs to each receptacle outlet.
The first one shows the method with the neutral conductor in the switch box. This page contains wiring diagrams for household light switches and includes. This option also has split receptacles as well as non split receptacles. Wire the 4 way according to the instructions that come with it.