I have tried them all. The router does not connect. The straight wire modem to desktop works fine. Also the link light on the cisco modem is orange and blinking even when connected. I have no documentation on the modem.
DHCP. You need to properly powercycle/reset the modem each and every time that you change the device that is being directly connected to it by removing the A.C. power for a minute. If it is a telephony type modem (eMTA) that has a built in backup battery then you'll need to use the recessed reset button on the rear instead of powercycling it