24 hours in the life of a (flakey) ADSL line
A signal-to-noise ratio graph from a Speed Touch Home. The
0-255 scale represents the DMT carrier number. The 0-143 scale is
time in 10-minute intervals since Midnight, and the 0-50 scale is
the operational channel S/N ratio in dB.
Some notes:
- Carriers 0-7 are unused (this is the voice band).
- Carriers 30-37 are unused (this is upstream/downstream
guard band).
- There is degradation at Carrier 181.
- There was a significant disruption of service at about
700 minutes after midnight (just before noon), followed by very good quality
across all carriers.