Sending Messages across the GPIB

Devices on the bus communicate by sending messages. Signals and lines transfer these messages across the GPIB interface, which consists of 16 signal lines and 8 ground return (shield drain) lines. The following sections describe the 16 signal lines.

Data Lines

Eight data lines, DIO1 through DIO8, carry both data and command messages.

Handshake Lines

Three hardware handshake lines asynchronously control the transfer of message bytes between devices. This process is a three-wire interlocked handshake, and it guarantees that devices send and receive message bytes on the data lines without transmission error. The GPIB Handshake Lines table summarizes the GPIB handshake lines.

Interface Management Lines

Five hardware lines manage the flow of information across the bus. The GPIB Interface Management Lines table summarizes the GPIB interface management lines.