| 摘要 |
A line interface unit (LIU) is designed to code 400 kbps signal form CCU by B8ZS line code rule and to transmit coded signla in 3 unit via subscriber line. It also provides functions of equalization, timing regeneration and data regeneration. Finally the code signal is converted to 400 kpbs NRZ dat awhich is conveyed to common channel unit (CCU). The unit is composed of encoder/decoder (4) converting 400 kbps NRZ signal to B8Zs signal, vice versa, line driver and finishing unit (5), line equalizer (7), system timing selector (8) and generator (20), and data regenerator (6). The LIU feedbacks receiving signal loss, frame synchronization loss, and self-loop back command to CPU for alarming capability.
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