This object controls the test pattern used for Bit Error Rate Testing (BERT) on DS1 (T1/E1) transmission lines, allowing selection of patterns like all-ones, all-zeros, or pseudorandom sequences. The BERT test measures link quality by transmitting known patterns and counting errors to detect signal degradation or equipment faults. An operator configures this pattern and monitors the results to diagnose and validate the health of leased-line or circuit connections.