This variable represents the desired loopback configuration of the DS1 interface. Agents supporting read/write access should return inconsistentValue in response to a requested loopback state that the interface does not support. The values mean: noLoop Not in the loopback state. A device that is not capable of performing a loopback on the interface shall always return this as its value. lineLoop The received signal at this interface does not go through the device (minimum penetration) but is looped back out. localLoop The transmitted signal at this interface is looped back and received by the same interface. What is transmitted onto the line is product dependent. payloadLoop The received signal at this interface is looped through the device. Typically the received signal is looped back for retransmission after it has passed through the device's framing function.