Actually, bonded DSL does have to have certain CO work. For instance, the cards in the CO or remote , would have to support ADSL+2 ; and ports need to be in sequence. I have recently provisioned single ports on ADSL+2 and not GMT that have worked at 19M/2 at 3kft loops. As long as the cable pairs are ground bonded correctly, with zero bridge taps, it works perfect. VDSL is common to bonded, but only uses one pair.