Abstract: The present invention provides a circuit board tester for performing functional and in-circuit tests on one or more circuit boards. The circuit board tester includes a testhead for interfacing with one or more circuit boards and supplying the resources for the testing thereof. The testhead includes a plurality of modules with each module having a defined amount of resources and a processor for use in executing a test plan to test the circuit board. The circuit board tester further includes a high-speed link for coordinating the execution of a test plan by two or more modules when the resources of one module are insufficient to test a particular circuit board. Each module in the testhead can be selectively connected or disconnected from the high-speed link. Consequently, two or more modules can be connected to the high-speed link to test a first circuit board while another module, that is disconnected from the high-speed link, can concurrently test a second circuit board.