Sometimes a Vendor will offer you termination via a number of different quality/price routes. You may receive a number of prefixes which will allow you to connect to a particular route.
Setup Connection and Tech Prefix
If a vendor has one IP address for all incoming traffic and then offers different routes based on the prefix (which may be different than the prefix used by the customer to select a routing plan), you would need to define a separate connection for each of those vendor prefixes.
Create a connection (under the vendor) for each tariff involved in your route plan and include a tech prefix; which is the number the customer will dial before the destination number to connect via that particular tariff .
You would also need to define the Outgoing Rule to add the prefixes to the dialed number (e.g. s/^/100/;) and a Translation Rule to remove the prefix for billing purposes (e.g. s/^100//;). Note that this step is not a PortaBilling requirement, but may be required by the vendors .