A method and apparatus for synchronizing digital and analog/mixed signal modules in a test site of an open architecture test system is disclosed. Event triggers from digital modules are routed to an ASYNC module, which selectively distributes them to analog/mixed signal modules. When an event occurs, the trigger may activate an analog/mixed signal module to perform a certain operation. The ASYNC module may also receive triggers from the analog/mixed signal modules and selectively distribute them back to the digital modules or analog/mixed signal modules. The digital modules can be programmed to wait for an analog/mixed signal module to complete an operation, as indicated by a trigger received from that analog/mixed signal module, before continuing. Because embodiments of the present invention enable synchronization of digital and analog/mixed signal modules under pattern control, synchronization can be very precise and repeatable as compared to synchronization from a site controller.