Techniques are described that can be used to identify a defective communication channel in a communications network. A decoder in a receiver may decode a signal received from a network. The decoded signal may be re-encoded and compared with the signal received from the network. A count of differences between the re-encoded signal and the signal received from a network may be provided. An indication of errors remaining after the decoding may also be provided. Based on the count and the indication, a defect in the communication channel may be identified. A user may be notified and/or actions may take place.