A read-write enumerated value setting the minimum data rate the fallback mechanism will attempt to train at, with "none" disabling the fallback feature entirely. This lets an admin allow a marginal line to automatically fall back to a lower, more reliable rate rather than failing outright when it can't sustain the primary configured rate. On a line that intermittently fails to train at its configured rate, the admin would set cmHDSLModemMinRate to a lower step so the port can fall back and stay in service instead of going down entirely.