connection -how many wires are required?

I have just connected my visonic powermax complete to my vera lite using a visonic dual rs232 module and a 3,3v USB to serial cable adapter [url=http://www.ebay.com/itm/New-USB-to-TTL-Serial-Cable-Adapter-FTDI-Chipset-FT232-USB-Cable-Computer-Cable-/400754040301?ssPageName=ADME:L:OC:US:3160]http://www.ebay.com/itm/New-USB-to-TTL-Serial-Cable-Adapter-FTDI-Chipset-FT232-USB-Cable-Computer-Cable-/400754040301?ssPageName=ADME:L:OC:US:3160[/url]
When reloading i get the error message not starting due to too many communication errors
I am unsure if i have connected everything correct, i am only using RXD TXD and GND is that enough?

Should be, I use an ethernet coverter and hooked it up like in this post: http://forum.micasaverde.com/index.php?topic=26660.msg193120.msg#193120
The module you use doesn’t need the power from the powermax, so 3 is enough.

I had the same problem.
Dont use the + wire, so as hoekstra described only use RXD TXD and GND.
And in your powermax alarm panel device under advanced tab clear the commexeptions field and reload luup.

I only use RXD, TXD and GND, i have tried to clear commexeptions field, same thing happens: at first nothing, later the same error message. Does it matter what RS232 port i use on the dual rs232 pcb?
What logs should i look in to get more info on what is happening?