The pwr led might stay in a blinking state if the RRC has connection(link up) with the router it's connected to but the router or some other equipment behind it doesn't have connection to the DNS server the RRC uses. In that case the 15 seconds delay the RRC uses after it has detected a connection(link up) to the router elapses without it being able to DNS resolve the SIP contact.
But if the network cable is disconnected in the RRC end, then the the pwr led should stop blinking when connecting it(assuming the aforementioned connection to the DNS Server is working)