Under normal operation, the AI-5120's front panel Ready indicator is illuminated continuously. However if an error condition is detected by the AI-5120, it begins flashing the Ready indicator. In this state, the Ringing and Off-Hook front panel LEDs are used to indicate the fault condition.

The following table lists the various fault conditions along with possible corrective actions.

READY Indicator	RINGING Indicator	OFF-HOOK Indicator	Description / Corrective Measure
Flashing	On	On	RAM Test Failure: Upon power on a check of the system RAM is performed. This fault condition indicates that the internal memory failed to store the correct data. As this represents a hardware fault, the only corrective action is to return the unit for repair.

The following fault conditions may occur if the internal flash memory becomes corrupted. The corrective action for all these conditions is restore the memory by using the Firmware Update software. If the firmware update program does not correct the problem, please contact technical support for assistance.

READY Indicator	RINGING Indicator	OFF-HOOK Indicator	Description / Corrective Measure
Flashing	Flashing	Off	Flash Memory Corruption Missing unit ID code: The unit ID code stored in the flash memory is either missing or is corrupted.
Flashing	On	Flashing	Flash Memory Corruption Missing calibration item(s): Either the calibration factors or the calibration script is missing from the flash memory or is corrupted.
Flashing	Flashing	Flashing	Flash Memory Corruption No boot script file: The startup script file is either missing from the flash memory or is corrupted.
Flashing	Flashing	On	Flash Memory Corruption Missing system script files: One or more system script files is either missing from the flash memory or is corrupted.
Flashing	Off	Off	Flash Memory Corruption No program file: The primary DSP application program is missing from the flash memory or is corrupted.
Off	On	Off	Flash Memory Corruption Failure to boot primary application: This fault condition is a special case in which the Ready indicator does not flash, but is off. It occurs when the primary DSP application program fails to boot and indicates a corrupted file within the flash memory, or a hardware fault.

The following fault condition indicates a serious error detected by the firmware. As the unit becomes unresponsive in this condition, the power must be cycled to restore normal operation.

READY Indicator	RINGING Indicator	OFF-HOOK Indicator	Description / Corrective Measure
Very Fast Flashing	Very Fast Flashing	Very Fast Flashing	Program Stack Fault The firmware has encountered a stack fault. This error prevents the device from responding to any commands and effectively freezes the system. The power must be turned off and then back on in order to restore normal operation. Please contact technical support if this error occurs as it represents a serious firmware error.