A read-write enumerated value that sets or displays the configured HDSL data rate for this port, chosen from fixed steps such as 160, 416, or 1568 Kbps. The admin selects a rate here to match what the copper pair can reliably support, trading off higher throughput against a higher chance of training failure on longer or noisier loops. On a long, marginal loop that keeps failing to train at 1568Kbps, the admin would lower cmHDSLModemDataRate to a smaller step like 784Kbps to get a stable, if slower, connection.