| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a conversion apparatus for maintaining clock synchronism between an IP network and a synchronous communication network even if abnormality occurs to the IP network. <P>SOLUTION: A clock selection unit 17 selects as a reference clock one of a first clock based upon a special packet, a second clock based upon a clock of the synchronous communication network, and an external supply clock. Then the conversion apparatus 10 converts an IP packet into frame data suitable to an I431 line according to the selected reference clock, and sends it out to a radio base station main device 101. Further, the conversion apparatus 10 monitors missing of an IP packet and loss of synchronization of the reference clock. When the second clock or external supply clock is selected as the reference clock, the conversion apparatus 10 does not send an AIS (Alarm Indication Signal) to the radio base station main device 101 and sends a frame synchronous signal out on condition that loss of synchronization does not occur in the reference signal even in case of missing of an IP packet. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
