# Timeouts

A timeout mechanism regulates the GPIB routines that transfer command sequences or data messages. All I/O must complete within the timeout period to avoid a timeout error. The handler uses a default timeout period of 10 seconds. You can use ibconfig to change the default timeout value. You also can use the ibtmo function to alter the timeout period.

Regardless of the I/O and wait timeout period, GPIB enforces a much shorter timeout for reading responses to serial polls. This shorter timeout period takes effect whenever you conduct a serial poll. Because devices normally respond quickly to polls, you do not need to wait the relatively lengthy I/O timeout period for a nonresponsive device.