Cosy 141 serial port documentation

Trying to setup a 141 to connect to an old S7-200 via the serial port. I remember there once being a document with the setup procedure and pinout for the cable, but I can’t seem to find it anymore. Can somebody help me out?


I think this might be what you’re looking for:


Awesome thanks! Is there a manual for establishing serial connection specifically to an S7-200?

It looks like these are the options with an S7-200

This might be useful for you. I don’t think it was specifically written for a 141 though.

1315753.pdf (1.7 MB)

So, reading the two documents you’ve sent me, I’ve found a (potential) discrepancy. It seems like the pinout should be:
eWON > S7-200
3 > 8
5 > 5
8 > 3

I got to this based on cross-referencing the below two pinouts:
Siemens S7-200 serial pinout

However, looking at the latest document you sent me, it shows a straight-through pinout:

eWON to s7-200 pinout

Which should I use and why?


Sorry it does look like there’s some conflicting information about which side is A and which side is B. Unfortunately I don’t have one of these devices to test which is correct currently, but would it be possible to test both wirings and check which one seems to be reading?


If not I can try and escalate this with a colleague in Belgium tomorrow morning and see which should be the correct pinout

Working on that now. Unfortunately it’s a device that’s already out in the field. It doesn’t look like the straight through cable is correct though (that’s the one that we made originally). We’re soldering up the crossover one now, and soon as that gets made I’ll test it out here in the shop before sending it out. Will keep you updated.

Ok thanks, I’ll send my colleague a message and see if he can give me some info on this as well

Ok, so it looks like neither configuration is working, which means that I must be doing something else wrong (though I still do need to know which pinout is correct).

So I setup the eWON as normal, and I can connect to it just fine. Then I go to the Gateway wizard, and select ISOTCP to PPI (Siemens S7-200). Then I put in the COM setup information that I get from the Step7 software used to program the S7-200. Then I go to the Communications settings in Step7, and change the PG/PC interface to TAP-Windows Adapter V9, and then search for the eWONs LAN address.

That should allow me to remotely connect to the PLC, correct? Am I missing a step?

My colleague let me know that the second picture should be the correct one.


I’ve been looking around trying to find an example of setting up a Cosy 141 using serial with S7200 but have been having some issues finding information. I think that ISOTCP might be limited to ethernet connections.

I’m going to check with a colleague in Belgium tomorrow to find out more about this


Any update on this?

I haven’t heard anything back yet, I’ll try and ping them again

They are saying that it should be possible by using this document as a template with the PPI connection: