Firstly you will need to login to the unit , go to System -> Digital -> Channel type, then select the configuaration that supporst IP. An IP camera is then connected to this unit via it's RJ45 (lan port) using a network switch or POE switch.
Are they in grey?
These are only available in white.
Can this be connected to an analogue only DVR?
This is a TVI only camera so will only work on a TVI system.
Are these HD cameras?
Yes, these are 2 mega pixel AHD (Analogue HD) Cameras.
will the connector take a 1mm digital coax?
This is not something it is designed to do i'm afraid.