Draytek Vigor2500V Manual page 113

VoIP
The hardware connection of Vigor2500V:
In most AnnexA (ADSL over POTS) countries, the subscription of ADSL and the
subscription of ISDN is separate. The Vigor2500V is highly recommended to
those who only subscribe the ADSL broadband access.
The hardware connection of Vigor2500Vi:
In Annex B (ADSL over ISDN) countries, the subscription of ADSL will let you get
the ADSL line box and ISDN NT1 from Telco/or ISP. The Vigor2500Vi will be
ideal product for you when you already have ADSL and ISDN. We let users of
AnnexB environment can fully utilize ISDN line because Vigor2500Vi has ISDN
interface.
If your ADSL environment is Annex A, you can still additionally subscribe ISDN
line as backup/remote access. Or, you already had ISDN Internet access before
you subscribe ADSL internet access. Hence, the Vigor2500Vi will be much
suitable for you.
Vigor2500V: highly recommended to those who only have ADSL line
Vigor2500Vi: highly recommended to those who already have ADSL line and
ISDN line. Or, you plan to additionally subscribe ISDN line.
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