Abstract: A user-orientated telephone instrument including high-fidelity speech encoding, encryption capability and many function presently provided by centralized call processing is described. Utilizing an ADPCM encoding process including forward error correction, a high quality relatively noise immune signal is provided. To the user, the instrument appears as a unique electronic telephone which offers many special services to facilitate communications with other people and with computers. Advanced features such as optional hands-off voice on/off-hook control, personal identification by voice print and remote chart presentation are provided.

Abstract: Information pathways for communications among personnel, among computers, and between personnel and computers, in a local communication system, including remote communications via leased lines or the public network is described. To a public central office, the present invention appears as a private branch exchange (PBX), served by many trunks, WATS, and "Foreign Exchange" lines, and providing all the standard PBX services; to the remote leased facility, it appears as a standard tie line terminator or, if the remote is another ICS, as a logical tie line terminator for which several logical tie lines are combined into each leased T1 line; to the in-house computer, it provides switched connection to other computers or to terminals at up to 19,200 Baud modulated data, at 32K-Baud for native (internal system) data (including 2K-Baud of forward error correction), or up to several gigabits direct binary transmission (such as the transmission scheme used with NDS and ANR displays, etc.

Abstract: A pulse signal conditioner filters and equalizes signal pulses representing digital data whether or not obtained from a magnetic recording device. Modified low pass filters filter the pulse signals and also derive and feed forward the second time derivative of the filtered pulse signals. The filtered pulse and the second time derivative thereof are combined to slim the pulse. Further slimming is provided by delay line equalizers having three paths. A first path for attenuating the pulse signals, a second path for delaying the pulse signals for a first delay, and a third path for delaying the pulse signals for a second delay and attenuation. Pulse signals from the three paths are combined to further slim the pulse.

Abstract: A high speed magnetic disk recording system is described in which the recording medium comprises a substrate having a magnetic coating thereon, and a magnetic recording transducer is operated in physical contact with the recording medium. The magnetic transducer comprises a single crystal material on at least the surface which contacts the recording medium. The single crystal material has a high thermal conductivity, a low friction coefficient and a high surface energy so that, when relative motion is provided between the magnetic recording transucer and the recording medium, an attractive force is generated which maintains the magnetic recording transducer in contact with the recording medium so that high density recorded data can be reliably written and sensed without excessive wear to either the magnetic transducer or the recording medium.