* We usually have DB 37 receptacle (Female) connector of Kuper PC for Step/Dir port.
* Due to original pinout, in DB37, Step are pin #2~17, and Dir are pin #21~36. But in Db9 side, Dir are pin #2~5 and Steps are pin #6~7.
* Some cables in DB9 side, ch13~16 was wired as Ground in pin1 (or Pin18, 19). it is because on RTMC48 card, boards can setup to provide either +5v or Ground by adjusting jumpers (on board JP6, JP7, JP8). The 4th DB9 is wired as ground for Pin 1.