If you need to make a custom power cable for a monitor with a barrel power input, such as the Indie 7, 702 Touch, or Cine 7, here are the specs for the connector. The barrel connection has a nominal 5.5mm outer shell and 2.1mm center jack. The center is positive (+).
The monitors listed above can accept a DC input range of 10-34 volts DC.
This same connector is also used on the DCA5 faux battery and legacy monitors AC7, DP6, and DP4. The DCA5 accepts input voltage between 6-30 volts DC. The legacy monitors can accept an input voltage between 7-18 volts DC.