Patent ID: 6314097
Filing Date: 2001-11-06
Classification: H04J,H04L,H04Q

Abstract:
A transmission device which sends and receives signals, including overhead information, over transmission lines,the transmission device comprising:a first part which adds and drops overhead information every N bytes for each of the transmission lines where N is an integer greater than 2;a second part which assembles the overhead information concerning the transmission lines dropped by the first part into a first packet and extracts overhead information to be added from a second packet; anda third part which extracts the overhead information from the first packet and assembles the overhead information into the second packet,said third part comprising:a fourth part that converts data forming the overhead information terminated into continuous data;a memory that stores the overhead information supplied from the second part; anda digital PLL circuit including a counter generating a read clock applied to the memory from which the overhead information is read, and a controller which controls the counter in accordance with a frequency variation in the overhead information so that the frequency of the read clock is changed based on the frequency variation.