Thanks for the response BBK.
I have been in touch with VM following my initial post, (expected India got a very amiable scouser) and he said there was a problem with the modem (power, I think he said). Anyway he has arranged for an engineer to call out next Saturday morning. I'll let you know how I get on.
The readings you requested are below (I think)
K
Cable Modem Downstream
DS-1 DS-2 DS-3 DS-4
Frequency 298750000 306750000 314750000 322750000
Lock Status
(QAM Lock/FEC Sync/MPEG Lock) Y/Y/Y Y/Y/Y Y/Y/Y Y/Y/Y
Channel Id 1 2 3 4
Modulation 256QAM 256QAM 256QAM 256QAM
Symbol Rate
(Msym/sec) 6.952 6.952 6.952 6.952
Interleave Depth I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17
Power Level
(dBmV) 12.03 12.09 11.42 12.00
RxMER
(dB) 38.26 38.26 38.61 38.61
Correctable
Codewords 56931 56918 48277 0
Uncorrectable
Codewords 391 431 275 277
Cable Modem Upstream
US-1 US-2 US-3 US-4
Channel Type 1.0 N/A N/A N/A
Channel ID 3 N/A N/A N/A
Frequency
(Hz) 45800000 N/A N/A N/A
Ranging Status Success N/A N/A N/A
Modulation 16QAM N/A N/A N/A
Symbol Rate
(KSym/sec) 2560 N/A N/A N/A
Mini-Slot Size 2 N/A N/A N/A
Power Level
(dBmV) 38.25 N/A N/A N/A
T1 Timeouts 0
T2 Timeouts 0 0 0 0
T3 Timeouts 1 0 0 0
T4 Timeouts 0 0 0 0