| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain a PON system capable of receiving a downward frame even in a sleep state, as compared with the conventional method in which ONU has to be in communication with OLT established to prepare for an arrival of a downward frame, because the downward frame particularly for an incoming telephone call occurs at unpredictable timing and a downward frame cannot be received in an ONU sleep state because of suspended communication with OLT. <P>SOLUTION: The PON system uses an initiation signal monitoring circuit which reacts to a particular initiation signal having one-to-one correspondence with LLID. The initiation signal instructing restoration from the sleep state is monitored with low power consumption by the application of any one of the following three means (1)-(3): (1) means for transmitting a frequency modulated initiation signal with an identical light wavelength to data communication, to cancel the sleep state of an arbitrary ONU; (2) means for transmitting a frequency modulated initiation signal with a different light wavelength from data communication, to cancel the sleep state of an arbitrary ONU; (3) means for transmitting a digitally coded initiation signal with a different light wavelength from data communication, to cancel the sleep state of an arbitrary ONU. <P>COPYRIGHT: (C)2013,JPO&INPIT |
