Patent ID: 6111879
Filing Date: 2000-08-29
Classification: H04J,H04L,H04Q

Abstract:
A telephone service system for use in an asynchronous transfer mode (ATM) private network comprising:a public switched telephone network (PSTN) interface unit for performing pulse code modulation (PCM) with an analog telephone signal transmitted from a channel in a PSTN and converting the modulated data into a Conference of European Postal And Telecommunications Administrations (CEPT) frame before sending it to a subscriber, said PSTN interface unit performing the PCM with CEPT frame data received from a subscriber and converting the modulated data into an analog telephone signal before forwarding it to the PSTN;a first ATM cell processing unit for converting the CEPT frame data from the PSTN interface unit into an ATM cell and converting an ATM cell received from a subscriber into CEPT frame data before transmitting it to the PSTN interface unit;an ATM switching unit for switching the ATM cell received from the first ATM processing unit to the subscriber and switching the ATM cell received from the subscriber to the PSTN;a second ATM processing unit for converting the ATM cell received from the ATM switching unit into CEPT frame data before sending it to the subscriber, said second ATM processing unit converting the CEPT frame data received from the subscriber into an ATM cell before sending it to the ATM switching unit; anda subscriber line interface unit for converting the CEPT frame data received from the second ATM processing unit, into an analog telephone signal before sending it to a relevant subscriber, said subscriber line interface unit performing the PCM with the analog telephone signal received from the subscriber and converting the PCM data into CEPT frame data;said PSTN interface unit comprising a first tip/ring interface unit for performing the PCM with analog telephone signals of n channels transmitted from the PSTN switch before sending it to a subscriber, said first tip/ring interface unit converting PCM data received from a subscriber, into an analog telephone signal and first CEPT processing unit for converting the PCM data of 30 channels transmitted from the first tip/ring interface unit into one CEPT frame before outputting said PCM data through n/30 E1 channels, said CEPT processing unit receiving a CEPT frame through n/30 E1 channels and converting said CEPT frame into PCM data before transmitting it to said first tip/ring interface unit.