Sorry for the really late reply, I'm just getting back around to this.
When I run that command, that port loses connection and cannot negotiate with the AT&T gateway.
/ping src-address=192.168.xxx.1 192.168.xxx.71
I didn't see this answered and might be of use to someone. Yes, RJ45 serial like a Cisco cable. That's what I used on the RB2011 sitting on my desk right now.normis:
in the routerboarg webpage not sell the case indor for rb2011UAS-2HnD
rj45 serial port like cisco ??