Circuit and method for interfacing with vehicle computer

A method of communicating information between an onboard vehicle computer and a proprietary monitoring and programming device using a first protocol and for communicating information between said on-board vehicle computer and a second monitoring device using a second protocol, comprising the steps of:

• providing a first communication protocol using a bi-directional communication bus;
• providing a second communication protocol using said bi-directional communication bus for an omni-directional receive bus and a second bus for a complimentary omni-directional transmit bus;
• distinguishing between an identification message and a communication data packet and providing an output which is indicative of the distinguished message or data;
• switching automatically between said first communication protocol and said second communication protocol as a result of said output;
• and
• enabling reception of incoming messages while filtering a local echo of a transmitted message.

An interface circuit for providing bi-directional communication with at least one on-board vehicle computer under a plurality of different communication protocols, said interface circuit comprising:

• bi-directional communication means for providing communication under a first communication protocol:
• full duplex communication means for providing communication under a second communication protocol, said full duplex communication means including an omni-directional receive bus and a complementary omni-directional transmit bus;
• means for detecting connection of a diagnostic tool to the interface circuit and selecting one of the communication protocols for said. diagnostic tool;
• and
• feedback means coupled to the bi-directional communication means for enabling reception of incoming messages while filtering a local echo of a transmitted message.

An interface circuit for providing bi-directional communication with at least one on-board vehicle computer under a plurality of different communication protocols, said interface circuit comprising:

• bi-directional communication means for providing communication under a first communication protocol;
• full duplex communication means for providing communication under a second communication protocol, said full duplex communication means including a receive bus and a transmit bus for handling said second communication protocol, and said receive bus being provided via said bi-directional communication means;
• and
• means for detecting connection of a diagnostic tool to the interface circuit and selecting one of the communication protocols for said diagnostic tool.