... testing SYNCH and ASYNCH testingDTE and DCE emulation Bit code testing Pattern slip testing Signal loss alarm ... -1, and artificial code(7) Error code insertion: Bit error, Pattern slip, None single, Ratio 10-1~10 ... 1, 220-1, 223-1, and artificial code(6) Bit error, pattern slip, none single, ratio , 10-1~ ... structure: Word length: 5, 6, 7, 8(bits) Stop bit: 1, 2(bits) Odd-even check: odd, even, 1, 0, ...