RS232 cable, it’s always complicated.

[GGMM]

Hello,

Now my Oscilloscope Yokogawa is working, i tried to connect its RS232 DB 9 pins on my PC   to work with with some software

I had a cable on A...x that I liked because it ended with a male RS232 plug and had, it seems to me, a female-female adapter.

https://www.aliexpress.com/item/32708918256.html?spm=a2g0o.productlist.main.1.15bf62caD2RVTY&algo_pvid=98371c0b-379d-41d0-978d-53bc381df108&algo_exp_id=98371c0b-379d-41d0-978d-53bc381df108-0&pdp_ext_f=%7B%22sku_id%22%3A%2263745466606%22%7D&pdp_npi=3%40dis%21EUR%213.37%213.37%21%21%21%21%21%40212272e216792563159755975d071b%2163745466606%21sea%21FR%213599008081&curPageLogUid=4PTAxk0ranME


I thought, well, I’ll be able to connect either directly to a female DB9, or a male DB9 with the adapter.
But it doesn’t seem to work....
The adapter seems to be wire. ie 1 to 1, 2 to 2, etc.
So I wondered if this can work knowing that at least 2 and 3 should be crossed?
According to this site
https://radio.pagesperso-orange.fr/RS232.htm
   The female adapter should be at the best connected like:
5-5
4- 6.1
3-3
2-3
1.6-4
8-7
7-8
9 NC
Otherwise it is recognized on the CH340 USB port on windows. But NO connexion

Your ideas
cdt

[Swake]

Yep, you wrote it:
Tx to Rx
Rx to Tx

If both sides are DB9 the 2 goes to 3 and 3 goes to 2. It is actually simple

If you don't want to splice up your new cable you might want to acquire a "null-modem" adapter or cable.

Have a look at this:
https://en.wikipedia.org/wiki/Null_modem

[rhb]

Back when I was in grad school 35 years ago and needed to connect a lot of stuff via RS-232, I made a cable which has 2 red-green leds and a double pole double throw switch to reverse the connection.  It just requires flipping the switch until both leds are green and xon/xoff works.  I used it as test cable and once I determined what type I needed I made one up.  It's just 2, 3  & 7, so not much soldering.  I kept a toolkit with a small vise, iron, etc.  It's a huge boon when you don't have a manual.  I used DB-25s and have a full complement of adapters.

[GGMM]

Hi,

USB/RS232 cable reminder

I was wondering if the chip in the cable is a "smart" fact and capable of automatically detecting the direction of connections.
the female adapter is a straight fact.
You put the cable directly without adapter (you have a USB / RS232 male DB9), you add the adapter (simple straight F/Female 9 pin connector) you have a cable with a  USB / RS232 female DB9.
The circuit then manages the direction of the wires. (?)
I think it’s possible.
I’ll dig into that.

[GGMM]

hi,

it's good with an old adaptator.

Subject to be close