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Voice-over-IP FAQ


How do I use the Digit Map facility?

Digit Map enables you to set up rules for modifying dialled numbers, or varying the dialling behaviour depending on the number called. Digit Map is supported on the Vigor2820V series routers.

In the examples we'll use here, we will have already set up accounts with three different SIP/VoIP providers (or it could be three different accounts with the same provider actually). So, we have VoIP accounts 1,2 and 3 already set up on the router.

When you dial any number, the Digit Map table (below) is checked to see if the dialled number matches any of the numbers in the prefix number. The red letters on the left are just for reference later.

Digit MAp Example

Selecting a VoIP Provider by Short code

In our example 'A', we have set up three prefix codes "1" "2" and 3" and we can then use them to select which of our three SIP accounts we use. Firstly we need to strip off our chosen short code, as that isn't part of the actual dialled number, so we set the Strip option in the third column. Then for each of the three rules, note the setting in the right hand column - this corresponds to each of our SIP accounts. For the strip option, the OP Number field must also be set to the name as a the prefix; this defines the string to strip from the number before dialling. Now, when we dial any number, we can manually select which provider to use by dialling 1,2 or 3 before the actual phone number.

Using the Replace Option

The 'Replace' option (see example 'B') allows you to strip off a dialled prefix and replace it with other numbers. This might be useful, for example, if you want to dial local numbers without the STD code but your SIP provider requires it. For example, if you live in London you could dial "7999 1234" but your SIP provider needs "020 7999 1234" so the rules in section 'B' will replace a 7 or 8 at the start of any dialled number with 0207 and 0208.

Another example of using replace is shown in example 'C' and is where your SIP provider requires you to dial in international format, but you want to dial in national format. For example you want to dial 01274 999123 but your provider requires you to dial 0044 1274 999123 so we set up a rule to replace all numbers starting 01 with 00441 (and the same for 02, 07 and 08 in our example).

Select Account by Destination

In example 'A' we set up our own short codes to manually select which SIP account to use, but you can also select the account used automatically, based on the number dialled. In our example 'D' we have chosen to route all calls to the USA (country code 1) via account VoIP1 and Spain (country code 34) via account VoIP3.

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