It is used as a connecting part of the prototype, but it took time to investigate the EIAJ standard (RC 5320 A), and it would be greatly appreciated that the standard product can be searched by that standard.
It sometimes does not appear as a specification in the product, I checked the dimensions by looking at the drawing of this document, I am thankful that the drawing is on it, although it was this product plug, it was about to miss with the picture of Jack.
Tepra's DC jack is L-shaped and always feels like a burden on the wiring. For that reason I disconnected internally, but the AC adapter was unexpectedly large in capacity and ordered here because Jack of Category 4 was not on hand. I could use it without any problem.