Issue with DB9 to DB25 adapter

Thread Starter

Xavier Pacheco Paulino

Joined Oct 21, 2015

I have a control panel which has a db9 male connector. It's used to program certain parameters of a sewing machine. If you would like more details, the control panel is an Efka Variocontrol 820. The point is that I have an older model of the sewing machine which uses a control panel with a DB25 male connector. Since I have the more recent model (Variocontrol 820 with DB9 connector), I would like to use it to program the older model which has a DB25 connector. I've seen people doing this through an adapter. But I don't have the adapter, instead I have two raw connectors DB9 female and DB25.
I have seen differents ways to make this adaptation on the web, but none of them works. Some of them are attached. So I was looking into the control panel (DB9 connector) and realized that VCC signal (5V) is connected to pin 4 and ground signal (GND) to pin 5. In the sewing machine (DB25 connector), pins 5 and 11 are VCC (5V) and pins 8,10 and 13 are ground (GND), so it's quite different from what appears in the internet. Do you know where can I find a complete conversion diagram DB9 to DB25 that matches this specific way of communication?



Joined Jul 18, 2013
In the majority of cases now a 3 wire cable can be used and the handshake can be jumpered out each end 4-5 & 6-8-20 on the 25 pin side and 1-4-6 & 7-8 on the 9D side.