I'm pretty sure I've still got a cable feed. Just used Robin Walker's DocsDiag to interrogate the CM. This is what I got.
DocsDiag v030720 Copyright 2001-3 Robin Walker
rdhw@cam.ac.uk
Terayon DOCSIS Cable Modem: <<HW_REV: 6.62; VENDOR: Terayon; BOOTR: NONE; SW_REV: 1.7.14; MODEL: >>
System up time = 0 days 00h 00m 19.81s
Downstream channel ID = 0
Downstream channel frequency = 0 Hz
Downstream received signal power = 4.1 dBmV
Upstream channel ID = 0
Upstream channel frequency = 0 Hz
SigQu: Signal to Noise Ratio = 17.7 dB
Cable modem status = Not synchronized
Upstream transmit signal power = 8.0 dBmV
Date and Time = unset
Configuration filename =
Seems a bit strange that the configuration filename is blank, or does it only get this if it establishes a link?