First DS3/E3 multi-channel LIU and framer combination device has integrated jitter attenuation

Fremont, California, — Exar Corporation, a provider of high-performance, mixed-signal silicon solutions for the worldwide communications infrastructure announced the industry's first DS3/E3 LIU/Framer/JA combination device family that leverages the Company's pioneering R3 technology. These devices follow Exar's successful single channel part, the XRT79L71 by adding multichannel integrated parts allowing customers to reduce board space and an easy upgrade path from two to four channels on the same board. Targeted applications include access equipment, digital cross-connect systems, routers, 3G base stations and Digital Subscriber Line Access Multiplexer (DSLAMs), or virtually any network switch equipment including ATM, WAN, and LAN.

All product family members leverage an integrated ATM UNI/PPP physical layer interface with on-board framers, and LIUs with JA. This family is designed to support ATM direct mapping and cell delineation, as well as PPP mapping and frame processing and clear channel framing. In addition, the devices have Exar's proprietary R3 Technology (Reconfigurable, Relayless Redundancy) whose characteristics, not offered by competitors, give customers the agility so that they can quickly respond and reconfigure devices for compressed design cycles without the unnecessary stock piling of inventory for all configurations. The XRT79L74 (four-channel), XRT79L73 (three-channel) and XRT79L72 (two-channel) share a common 456-PBGA packaging platform and pin-out enabling the designer to support one board design for two, three and four-port applications.

R3 Technology Overview
Exar's R3 Technology (Reconfigurable, Relayless Redundancy), first introduced in 2002 as a breakthrough capability delivering key benefits to customers designing T1/E1/J1 interface cards has now been extended to the higher speed DS3/E3 environment. The devices are frequency and mode Reconfigurable enabling customers to build one board with a single bill-of-materials. In addition, the series employs Relayless Redundancy eliminating the need for external relays for 1:1 and 1+1 applications by establishing a back-up channel that can be brought on-line in the event of failure.

The XRT79L74/73/72 incorporates all the necessary interfaces for varied DS3/E3 applications. These include ATM UNI applications, the ATM physical layer interface utilized in public and private DS3/E3 networks, as well as the industry standard UTOPIA II and POS-PHY interfaces. In addition, they have a flexible parallel microprocessor interface (8-bit wide Intel, Motorola or PowerPC) for easy device configuration and control. In clear channel framer applications, the devices support transmission and reception of user data via the DS3/E3 payload. All the devices support mapping of ATM or HDLC framed data. All devices support E3 (34.368.Mbps) and DS3 (44.736Mbps) modes of operation. Each device contains an onboard Pseudo Random Binary Sequence (PRBS) generator and detector with the ability to insert and detect single bit error. This function can also be used for diagnostic purposes.

The LIU meets jitter and wander specifications described in the T1.105.03b, and ETSI TBR-24, and is compliant with Bellcore GR-499 and GR-253 standards, and the framer meets G.832 and G.751 standards, plus the T3 framer meets ANSI T1.107 and T1.404 standards. The devices perform transmit packet processing where PPP data packets are inserted into the data stream; the extraction of in-band messaging packets completed, and there is also support for CRC-16/32, and HDLC flag and idle sequence generation. When receiving packets, the device extracts a HDLC data stream from the DS3/E3 frame, inserts in-band messaging packets and detects and removes HDLC tags. Additionally, the devices have programmable FIFO size for both the transmit and receive direction, and have a serial clock and data interface for accessing both DS3/E3 framer and cell/packet processors.

Samples of the XRT79L74, XRT79L73 and XRT79L72 are available now, and priced at $159.62, $127.46 and $84.97 respectively for 1,000 units. All parts are packaged in a 456-pin PBGA package and operate at the industrial temperature range of -40 to 85 degree C. Evaluation boards are also available to assist with hardware development.

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