... Attenuator Plug Type 2.optional connectors: FC/UPC,FC/APC,SC/UPC,SC/APC,LC/UPC ... In line1-30dB1~5dB<±0.1dB1310nmInsertion loss:FC/UPC1550nm≤0.2dB (UPC)FC/APC1310nm/1550nm≤0.3dB (APC)SC/UPC ... ,SC/APCReturn loss:LC/UPC,LC/APC5~10dB<±0 ... eight times/direction changes insertion loss more than 0.1 dBReference standards001209 Bellcore TA - NWT - ...