The power consumption of the subrack is tested in the following conditions:

• Working voltage: -53.5 V DC.
• Ambient temperature: 25 °C.
• Static power consumption: All ports do not carry any loads. Specifically, users under POTS ports hang up phones, xDSL ports are deactivated, and optical modules are not installed on optical ports
• Maximum power consumption: All ports fully carry loads. However, only 25% users under POTS ports concurrently pick up phones and the feeding current is 20 mA.
• Typical power consumption: half of the total value of static power consumption and maximum power consumption.
• The preceding table lists power consumption under typical configuration. For power consumption under other configurations
• In the case of Access device, power consumption is generally transformed into heat consumption. Hence, heat consumption (BTU/h) and power consumption (W) can be converted to each other in the formula: 1 BTU/h = 0.2931 W.