This object sets the per-DS0 data rate for timeslots in this bundle, 56kbps if robbed-bit signaling is used on a T1 line, or 64kbps for clear-channel signaling, and per the description E1-based DS0s should always use 64kbps. Getting this wrong on a T1-based bundle mismatches the bundle's assumed capacity with what the actual line signaling supports, since robbed-bit signaling on T1 steals a bit per frame for signaling purposes and effectively caps usable payload per timeslot at 56kbps rather than the full 64kbps. An admin provisioning a bundle over a T1 line still using older robbed-bit signaling would set this object to rate56(1), and setting it to rate64(2) on that same line would overstate the bundle's actual usable bandwidth by roughly 12.5%.