Abstract: A user network interface device for interfacing between synchronous optical network (SONET)/synchronous digital hierarchy (SDH) which is characterized by a continuous stream of frames of data and an asynchronous transfer mode (ATM) characterized by a non-continuous stream of cells of data. The user network interface device includes an integral phase lock loop circuit to recover clock and data from an encoded incoming stream of data. In another embodiment, the network interface device synthesizes a high speed transmit clock from a low frequency reference source.

Abstract: An ATM layer device for interfacing between a physical layer device and an ATM switch, which includes means for prepending and postpending of switch routing information to cells destined to enter the switch and for removing such information from cells having left the switch

Abstract: A series of hard disk drives are secured atop molded plastic support trays slidably and removably received in opposing guide channel member pairs snap-fitted into opposite side walls of a sheet metal cage structure externally used in conjunction with a file server or other computer device. Snap-fitted into rear end portions of the trays are small printed circuit boards that are insertable into hot plug sockets at the rear of the cage. Forwardly projecting guard plates on the rear end of the cage block manual access to the board/socket interface, and the surface mounted grounding leads on the board extend rearwardly beyond its signal leads to enhance grounding safety during disk drive installation and removal. At the front end of each tray is a vertical support plate upon which LED indicating lights are conveniently mounted for the associated disk drive.