Span interface module for a telecommunications switching platform

An interface module capable of responding to heartbeat messages and identifying itself as operational over one bus or both buses of a redundant-pair control bus. The module also has a reprogrammable, nonvolatile memory associated with it from which the module can run its operating code. The module can also transfer the operating code into another memory, allowing it to make updates to the operating code stored in the nonvolatile memory without interrupting its execution of its run-time operating code.