I have a CPU 313C and CP341 and the GPRS modem MD720-3 connected via RS232 serial to the CP and in the SIMATIC user program I copied all the related blocks to my program but I don't know what to do with these block ( UDT91,UDT92, FB_WDC_INIT,FB_WDC_SEND , e.t.c ..)

Do i need to put it in the OB1 of the program or just leave it outside?

I tried to do so but the CPU gives me SF error after download..I've read all the manuals with nothing new to do...I opened UDT91 and defined parameters for the modem...What else to do with the blocks?

Is my program OK ? or Am I missing something ?

The modem LEDs (Q) is on and (S) blinks slowly but never ON also (C) is off

I used a PINless SIM card in the modem

In the PC there's no DSL router available for me so i tried to connect to INTERNET using a Vodafone USB stick modem...Is there a way possible to forward the port 26862 in the USB modem ?

In case any other details needed please notify me.