| 摘要 |
An ATM (Asynchronous Transfer Mode) cell format conversion system writes in a memory a plurality of ATM cells each being 53 octets long and mapped in the payload fields of virtual containers VC-4-NC which have been multiplexed in the form of STM-N frames and have been extracted from said frames. A 1 octet-long cell overhead is added to each of the ATM cells read out of the memory in response to base frame pulses which are synchronous with the STM-N frames, whereby the ATM cells are converted to 1-octet-added ATM cells each being 54 octets long. The 1-octet-added ATM cells and an idle cell are mapped in an imaginary matrix 5 column groupsx9 rows frame by frame and then outputted. This allows each of the STM-N frames or be switched to otherwise processed on an ATM cell basis.
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