An improved interconnection protocol that is well suited for use in an inspection system or similar modular electronic system. Communication is provided over a network where the electronic modules are nodes, including a root node and multiple remote nodes. The root node and remote nodes are connected through multiple point-to-point synchronous links. The root node and remote nodes are configured to send and receive packets in either a short form or a normal form. Timing between the root node and remote nodes is provided by an external clock distributed by the root node. Each remote node responds to commands with low latency. This protocol allows normal packets to be configured to provide variable payload length, with a maximum payload size that yields a low protocol overhead.