At the core of the SBC Edge Portfolio system's call routing logic are sets for Regular Expressions used for selecting, and transforming called numbers and addresses. In the SBC Edge Portfolio, regular expressions are defined in Transformation Table Entries which are attached to Call Route Entries. Regular Expressions defined in Transformation Table entries are used to select calls for routing, typically based on the called number or address of the call. The following pages provide examples of Regular Expressions for selecting and transforming called numbers and addresses and a further discussion of Regular Expression Syntax: