... emulation Bit code testing Pattern slip testing Signal loss alarm Line signal level and frequency testing Loop delay testingAutomatic protection ... : 120Ω, 26dB gainReflection loss >18dB within 50Hz3100kHz.(6) Signal structure(6.1) Non-frame structure(6.2) Frame structure: PCM30, PCM31, PCM30CRC, ... ,19.2k,38.4k,57.6kbpsData structure: Word length: 5,6,7,8bitsStop bit: 1,2bitsOdd-even check: odd, even, ...