The BERT pattern to be sent and expected to be received. twoE9MinusOne(1): This is 2^9-1(511 bits in length) pattern specified in ITU O.153. It has the maximum of 8(non-inverted) sequential zeros and 9 sequential ones. twoE11MinusOne(2): This is the 2^11-1(2047 bits in length) pattern specified in ITU O.152, O.153. It has a maximum of 10(non-inverted) sequential zeros and 11 sequential ones. This pattern is primarily intended for error measurements at bit rates of 64kbit/s and N*64 kbit/s. twoE15MinusOne(3): This is the 2^15-1(32767 bits in length) pattern as specified in ITU O.151. It has the maximum of 15(inverted) sequential zeros. This sequence is primarily intended for error and jitter measurements at bit rates of 1544, 2048, 6312, 8448, 32064 and 44736 kbit/s. twoE20MinusOne(4): This the 2^20-1(1048575 bits in length) pattern specified in ITU O.153.It has the maximum of 19(non-inverted) sequential zeros. This pattern is primarily intended for error measurements at bit rates up to 73kbit/s. This pattern stresses the equalization and timing recovery circuitry of line repeaters. twoE23MinusOne(5): This is the 2^23-1(8388607 bit length) pattern specified in ITU O.151. Highest stress pseudo-random pattern, with a maximum of 23 (inverted) sequential zeros and 23 sequential ones. This sequence is primarily intended for error and jitter measurements at bit rates of 34368 and 139264 kbit/s. userPattern(20): This is any user defined pattern.