SINUMERIK 880 has 4 COM ports, but only #3 , the one  on the COM CPU in the CNC rack can make communication with STEP 5 SW.

Port#1, #2 on the back of display while COM #3 and #4 on the CPU in the CNC rack, the far left side control card the top one port (D type 25 female)

do you have cable for transfer data such as NC program from Laptop to 880, using the same cable, if you don't have cable search by Google "RS232 cable pinout 25 to 9 " make one or buy from Electrical store from local or online

setting data should be :

SD 5030=0000100 SD 5031=1000111 

select Data I/Out--interface #3--> Data In--> start  (press Start 2 times, you will not see DIO but message Data in Active) 

STEP-5 side --going to Projection--PLC , using F3 to online or off line

M. M1365

Hi Dear

Can you help me?

I want connect plc s5 software to sinumerik 880t.

I have s5 windows in my laptop. 

But i don't Know, How can i online with port x121.

Help me please. 

 Happy New Year

I mostly showing you on 880T side, I see you working well on PC/Laptop side with STEP 5 

try and give feedback

Thank you for Reply me. 

I have a cable 25 pin to 9 pin to usb.

I inestalled drivers software. And i checked in device manager saw Serial poro (com3)

And i saw drivers com Convert  to usb.

I hope i can connector. 🙏 

#1--make sure your RS 232 cable is good, you use cable tester or use this cable to transfer NC program to 880 from your PC, 

#2--If the cable is good. Try to change COM3 to COM1--if you cannot , ask PC expert 

I thought STEP 5 can only use COM1

M. M1365

Hi ,happy new years

I couldn't connect .

I connected with USB cable , my laptop doesn't have com port .

when i press online shows a red message " link not fount".