Siemens S5-95U connection cable

German-made machine has S5-95u processor. I need to download its program to my laptop, but don't have the correct cable. I've been told that I need the 6ES5734-1BD20 pc/tty converter, which I think is a 25-pin to 15-pin configuration. I've seen some threads that have a PC/TTY converter, but the one I've seen has an AG/TTY label...but same part number. Is there a differrence?

The PC/TTY converter is an RS232-20mA current loop converter. Siemens PGs (Programmier Geräte) have the current loop converter built-in and use some free pins on a 25 pin RS232 connector. Never use the AG/TTY cable on a PC, it won't work. Normally it shouldn't damage anything either.

Kind regards,

Thanks for the info on the AG/TTY cable. We have that cable here...but not the PC/TTY. The real problem here is the recent layoff of most of our R&D Engineers, who had most, if not all of the machine programs and interface cables to the processors. This seems to be the case here...engineer is gone...so are the items I need! I have heard that there may be a Siemens PG floating around in the vacant R&D offices though!

we use the Black Box RS232 <-> CL converters. A standard 9 pin to 25 pin serial cable is connected to the RS232c end of the converter, then a 15Pin cable is fabricated to attach to the CL end of the converter which has screw connections.

Ian Phillips
flomation engineering

Would you happen to know the Siemens part# for this PC to PLC (RS232 current loop converter)? Many thanks.

I believe the part number is 6ES5 734-1BD20

You can also make your own, Click here for link


Download the CAD drawing for the RS232 to 20mA converter

Paul