I just received this answer from Honeywell technical support:
"The cabling is as follows on the GSM connector pins on the panel, : +12 / 0 / D / C from left to right. The cable is straight, so on the GSM module the order is the same. Make sure you position the module correctly."
I find this all a bit confusing. Does anyone have a photo of the original cable?
What would happen if the cable is connected wrongly, will the GSM module be destroyed?
I have attached a photo of my homemade cable.