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.
Annex A router uses RJ-11 for its DSL port.
Annex B router uses RJ-45.
For Vigor2860/2760/130 Series, Annex A router use black-colored DSL Port.
Annex B Router uses a gray-colored one.
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