Did you try to switch the Rx/Tx signal cables already? From the image of the cable it’s not clear whether the white (Rx) cable is the receiving signal cable in perspective of the PC or the device it’s attached to. If the labels corresponds to the functions on the PC side, the cables should be switched so that the Rx side of the Cellular module is connected to the Tx side of the PC (the green cable), etc…
I doubt however whether this is the problem since it seems that opening the COM port is already not working.
EDIT:
A few questions:
If the RX/TX/GND connections are not working, will windows then say “Cannot open COM port” or should I try to investigate connections?
Does it make sense to try on an older computer and see if that is better, my experience tells me that win 8.1 and serial with older chips sucks…?
If the error you are getting is “can’t open serial port” I suggest you try to debug that first.
A few comments:
with FTDI cables you don’t have to change settings in the control panel and/or driver details page. Suggest you uninstall the driver and install again to reset the settings.
try to disconnect the cable TX, RX from the module board and open it with the software. If it works there an issue with the connection.
also remove do the shunt for the control pin
SIM900 is power hungry, I can see you are not connecting the external power in the power module, only the USB. Suggest you connect the external psu to clear any power issues that the module may be experiencing
I can see that you are trying to use an extremely high baud rate. I doubt the SIM900 can safely handle that speed, specially when performing such an important task as updating the firmware. I’ve updated my SIM900 twice now and I’ve use 115k
@ njbuch - If you “can’t open serial port” the problem is not the sim900 board probably. You are facing ftdi driver problem. Have you installed on the PC TeraTerm or similar program?
Close all program related to firmware upgrade and disconnect ftdi cable from cell board and from PC. Reconnect FTDI cable only to PC, start Teraterm than try to connect to serial port mapped by the driver COMxx. If Teraterm can open it without any issue, this means FTDI driver is ok. Don’t set more than 115k bauds
@ dobova - then its a driver issue!! Becuase I have tried TeraTerm etc and all apps just show the “USB Serial port (COM13)” as available, but they cannot open it…
@ njbuch - Ah ok, that’s the problem. I suggest to remove FTDI driver from PC. Find right one for the chip you are using. I had a problem with FTDI chip drivers only when I had on the PC a driver for an other serial/usb chip (can’t remind … CP21xx something).
