How to tell if my ADSL router is Annex A or Annex B?

For ADSL/VDSL routers, there are two types of WAN interface. While Annex A is for ADSL over POTS, Annex B is for ADSL over ISDN. We may tell the annex type by checking the type or the color of the DSL port.

NOTE: Since there is a hardware difference between Annex A and Annex B, neither can we use an Annex A router on an Annex B line and vice versa, nor change the Annex Type by a firmware upgrade.

Port Type Difference

Annex A router uses RJ-11 for its DSL port.

Annex B router uses RJ-45.

Port Color Difference

For Vigor2860/2760/130 Series, Annex A router use black-colored DSL Port.

Annex B Router uses a gray-colored one.