Wiring Diagram For Jack - A modular connector is an electrical connector that was originally designed for use in telephone wiring, but has since been used for many other purposes. Many applications that originally used a bulkier, more expensive connector have converted to modular connectors. Probably the best known applications of modular connectors are for telephone and Ethernet.. This page contains information on the MegaSquirt Relay/Power Distribution board for the MegaSquirt ® EFI system. The relay/power board is designed to be installed in the engine compartment and interconnected to the MegaSquirt ® ECU using a remote cable. This allows the mounting of the MegaSquirt ® ECU in the passenger compartment, which keeps the ECU from experiencing the. LIST OF HARNESSES : 01 CBP battery positive cable. 02 CBN battery negative cable. 03 CB/AV connecting cable, front batteries. 04 CB/CE connecting cable, batteries to electronic unit..