# Verifying the board's operating temperature

The CX Devices Interface (CDI) service provides API functions for temperature monitoring on CX 2000 boards. Refer to the CDI Service Developer's Reference Manual for information about these functions.

Readings should be taken after running under a typical load (with a number of stations off-hook) for one hour. The following table indicates the maximum safe operating temperatures for various environments:

On-board temperature sensor ID | Maximum temperature reading in temperature controlled laboratory environment | Maximum field operating temperature
--- | --- | ---
0 | 65° C | 90° C
1 | 65° C | 90° C
2 | 60° C | 90° C
3 | 60° C | 90° C
4 | 60° C | 90° C

Exceeding these readings will cause warnings of overheating. Reduce the temperature in one of the following ways:

- Clean the chassis air filters.

- Replace a failed or underrated fan.

- Replace the chassis with one that provides more air flow. For chassis recommendations, refer to Selecting a PCI chassis.

- Improve room temperature controls.

CX boards that operate beyond the maximum field operating temperatures may exhibit one or more of the following symptoms:

- Events are sent to the application to warn of overheating. For more information about these events, refer to the CDI Service Developer's Reference Manual.

- New calls receive a strange tone in place of the dial tone.

- The loop current may be reduced. This reduction in current may impact the operation of telephones or other attached devices.