An adapter system has a standard adapter for intercoupling two first type connectors, and an interface converter for attachment to the standard adapter. Each first type connector has a first connection end formed with two engaged portions. The standard adapter has two first openings and two engaging portions within the first openings engaging the two engaged portions so that the standard adapter retains the first connection end when the first type connector is inserted in the first opening. The interface converter is attached inside the first opening to convert the first opening to a second opening having a second interface for a second connection end of a second type connector different in shape from the first connection end and has two receptacles for receiving the engaging portions.
