Caution: Each of the Phone ports can be connected to an analog phone only. Do not connect the phone ports to the telephone wall jack. Such connection might damage your router.
2.2 ISDN Phone Adapter Installation
Such information is provided for Vigor2820 S models (e.g., Vigor2820VS/VSn).
Phone S0 is always fixed to connect ISDN phone. However, ISDN /Phone S0 is configurable as NT or TE mode. When the user configures ISDN /Phone S0 as NT mode in VoIP>> Phone Settings, the orange LED will light on to indicate
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