In order to function, services transported over traditional HDSL require transceivers
at both ends — central office and customer premises — provided by a single
vendor. Standards currently being considered for its replacement, HDSL2, would
allow transceivers from different vendors to interoperate. The obvious benefit for
purchasers of such devices is the freedom to “mix and match” components from
different manufacturers, increasing competition and ultimately reducing costs.
But the real, long-term benefits of interoperability are less apparent and far more