A method and apparatus for adapting a backplane from one type of connector to another type of connector is disclosed. The method includes providing a backplane with a plurality of connectors, each connector being of a first type of connector, providing at least one extension module having a plurality of connectors, each connector being of a second type of connector, and plugging the at least one extension module into at least one of the first plurality of first type of connectors, thereby converting the first type of connectors into the second type of connectors. In a preferred embodiment, the backplane is used in a SONET communications system, and the conversion is from DS1 to DS3 connectors. The conversion allows an individual user to begin with one type of connector, and later expand as the need arises to an additional type or types of connectors.