Cisco Switching/Routing :: 3745 Router Failed To Exchange The Reference Signal

I am almost new to the networking field, hence I might have lacking some basic knowledge. I like to know the impact if the ground of any router get disconnect. WIll the router stops work?  We have two peripheral router in my organization, both are connect with the MPLS cloud through the MUX. One router (3745) have ground connection, where as the other (3845) don't. Recently the 3745 router start generating CRC error on the WAN interface. Once we remove the patch cord connecting with the MUX for loop test and reconnect later, the interface did not come back again. FInaly someone advice me to check the ground connection. I found it was loose. Once I fix it properly and reboot the router the interface become up. The person told me that some cisco router send the reference signal through the ground to the MUX connecting with it, if the MUX and router failed to exchange the reference signal the router will not work, is this true ?