Press Release
                        Contact:-
                        Aston Bridgman
                        NEC Corporation	
                        TEL    :81-3-3798-6511
                        FAX    :81-3-3457-7249
                        E-mail : Aston_Bridgman@HO-PRD.ccgw.nec.co.jp

*****For immediate use May 26, 1998

NEC Introduces ATM Physical Layer Device With Four Channel 155Mbps SONET/SDH Framer Function

ATM is a mode of communications that enables information multiplexing and routing by adding routing information to the header of each fixed-length transfer information unit (53-byte ATM cell). ATM is widely anticipated to become a key Broadband ISDN technology that can communicate multimedia information (including motion video) across networks by providing a variety of transmission rates and functions.

Used as a SONET/SDH framer in ATM network components such as ATM hubs and ATM switches, the NEASCOT-P40 is an LSI chip that performs the PHY layer function of the ATM protocol. The chip has two major functions. One is a send function that maps ATM cells received from the upper ATM layer to 155 Mbps SONET STS-3c/SDH STM-1 frames for transmission onto the line. The other is a receive function that extracts ATM cells from the data bit stream of frames received from the line, and transfers the ATM cells to the upper ATM layer device.

The µPD98411 has six major features:

• Four channel 155 Mbps SONET STS-3c /SDH STM-1 frame transmission function in single chip solution;
• Four receive data clock recovery circuits and clock synthesis function eliminate external LSI chip for clock recovery, halving mount area;
• Low power consumption of 1.6W (typical) on (3.3 V supply voltage, significantly cutting power consumption;
• Support for both UTOPIA (Universal Test & Operation Physical Interface for ATM) Level 2 16- and 8-bit modes as recommended by the ATM Forum for interface with ATM layer devices, ensures compatibility irrespective of manufacturer;
• OAM (Operations, Administration and Maintenance) function detects errors on each channel, while also monitoring the frequency and history of those errors; and,
• Self-diagnosis of receive function errors, as well as programmable function for outputting data on detected errors.

Background

As seen from the explosive proliferation of the Internet and mobile communication networks in recent years, the communications market is continuing to experience dramatic growth. One effect of this has been a focus on ATM technology for multimedia communications, and many actual applications of ATM are already being seen as the market takes shape.

NEC has been marketing its NEASCOT-series ATM LSIs, and has been enhancing its series of SAR, PHY and Switching devices. NEC's PHY devices, include the µPD98408 (a single-chip product with six PHY function channels on a 25.6 Mbps ATM 25 frame base) and the µPD98404 155 Mbps SONET STS-3c /SDH STM-1 frame base PHY device. Both products are found in a wide variety of equipment.

Continuing demand for more compact and lower-cost equipment, together with higher cost performance and lower power consumption needs, spurred NEC to respond with the µPD98411. The NEASCOT-P40 offers several advanced features that NEC believes will help contribute to the growth of the ATM market, while the company is already making substantial efforts to support this growth with future plans for other advanced LSIs.

For Main Specifications of the µPD98411, please see the attached sheet.

***

ATM -	Asynchronous Transfer Mode, In ATM, all information including voice, image, computer data, and so forth is digitized and divided into 48-byte units. Then, a header including information such as destination data is added to each unit of data to produce a 53-byte cell. This cell is the unit of transmission in ATM.
SDH -	Synchronous Digital Hierarchy, digital multiplexing plan where all levels are synched to same master clock,
SONET:	Synchronous Optical Network
SAR:	Segmentation And Re-assembly, protocol layer that divides packets into cells.
PHY:	Physical Layer 1 of the OSI model.