Under normal operation, the AI-5620's front panel Ready indicator is illuminated continuously. However if an error condition is detected by the AI-5620, 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
illuminated, but flickers off briefly once a second	any state	any state	USB Interface Not Connected: The USB interface is either not connected to the PC, the PC is turned off, a failure within the PC's USB port, or Windows has failed to enumerate the AI-5620. Ensure the AI-5620 is connected to the PC and the PC is operating normally. If this condition persists try a different USB port, USB cable, or reboot the PC.
Flashing	On	Flashing	Line Interface Protection: The line interface circuit has been disconnected from the front panel RJ-11 jack due to the detection of excessive line voltage or loop current. From within the TRsSim software, open the Error Log & Telephone Interface Status window. The current state of the protection system is displayed in this window. Click the Restore Tel. Int. Settings button to restore the line interface connection.

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	On	On	Flash Memory Corruption Missing configuration information: A unit configuration file stored in the flash memory is either missing or is corrupted.
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	Off	Flashing	Flash Memory Corruption Missing calibration item(s): One or more of the calibration factors is missing from the flash memory.
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 rather off. It occurs when the primary DSP application program fails to boot. It 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 AI-5620 firmware has encountered a stack fault. This error prevents the AI-5620 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.