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Voice messaging system
Network gateway connects up to eight LANS A network gateway device that links as many as eight remote Ethernet networks using common point-topoint connection media has been introduced by Bridge Communications. The GS/3 Internetwork Router is a communications processing system that supports from two to eight communication lines, with a maximum aggregate data rate of 304 Kbit/s when fully configured. The GS/3 can use any point-topoint connection method accessible via an RS232/423 or 422 synchronous communications port, including leased lines, fibre-optic links, point-to-point broadband modems, microwave links and switched lines. A network layer gateway, the GS/ 3 uses the XNS Internetwork Datagram Protocol to route information packets across multiple Ethernets or communications links, and the Routing Information Protocol to dynamically query and update internetwork routing tables. Internetwork packets, transferred at the rate of up to 350/s, are
encapsulated using a full-duplex HDLC-like framing protocol for high-performance transmission across any medium. Multiple links may be set up between any two Ethernet networks for increased throughput and redundancy. The unit consists of three logical modules, each incorporating its own dedicated 16/32 bit MC68000 microprocessor: the central communications processor, which contains the XNS protocol software, the Ethernet interface module, which interfaces to the Ethernet at the datalink level, the serial interface module, which contains one to four 68000-based serial I/O boards, each containing a pair of highspeed ports supporting an aggregate data rate of 76 kbit/s - - w h e n the maximum of four SIO boards are installed, eight communications lines are available. The Multibus (IEEE 796) backplane bus serves as a data path between
Voice messaging system Plessey Communication Systems have added an electronic voice messaging system to their IDX digital exchange. The Integrated Voice Messaging System (IVM) is a microprocessorbased digitized voice messaging system designed to increase office productivity by automatically answering routine calls then digitizing and storing voice messages in individual 'mailboxes'. The system allows the user to pick up, play back, save, edit, transfer and create messages while in or out of the office. By entering commands via the touch-tone command structure,
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the user is able to listen to each message (which is time-stamped with day, hour and minute of receipt), formulate a reply, cancel, save or transfer the message to another mailbox. Messages are played in order of receipt. Additional commands allow the user to broadcast messages to specific groups within the system. E a c h subscriber's mailbox is locked by a unique fourdigit identification code which must follow the user's voice mailbox address. (Plessey Communication Systems Ltd., Justin Manor, 341 London Road, Mitcham, Surrey, UK. -feh 01 646 4141) []
the three modules. A number of programmable configuration options allow the network manager to set such parameters as number and speed of each synchronous link, number and size of buffers and network identification for each Ethernet. The GS/3 also gathers full network statistics to assist in monitoring utilization, throughput, error rates, packet delay and other network measurements. (Bridge Communications Inc. 10440 Bubb Road, Cupertino, CA 95014, USA. Tel: 408 446 2981) []
TV pictures by telephone The Model 250 Transceiver from Colorado Video has been designed to provide visual communications over standard voice-grade dial-up telephone circuits. The transceiver takes a frame of video from a closed-circuit TV camera, digitizes it and converts the frozen picture to a 'slow-scan' television signal suitable for transmission over the telephone. At the receiving location the incoming signal is reconverted into a still image and displayed on a normal TV monitor. The time taken to transmit a complete picture is about 35 s. Slow-scan video is similar in concept to facsimile, but is more flexible in that any subject material which can be viewed by a TV camera can be transmitted. Applications include business or engineering conferencing between two or more locations, person-toperson visual communications, information retrieval, remote sensing, security, remote medical diagnosis and imagery, education and the interconnection of TV signals to computers for image analysis in scientific research. (Brian Reece Scientific Instruments, Unit B, Newspaper House, Faraday Road, Newbury, Berks., UK. Tel: 0635 3282 7) []
computer communications
encapsulated using a full-duplex HDLC-like framing protocol for high-performance transmission across any medium. Multiple links may be set up between any two Ethernet networks for increased throughput and redundancy. The unit consists of three logical modules, each incorporating its own dedicated 16/32 bit MC68000 microprocessor: the central communications processor, which contains the XNS protocol software, the Ethernet interface module, which interfaces to the Ethernet at the datalink level, the serial interface module, which contains one to four 68000-based serial I/O boards, each containing a pair of highspeed ports supporting an aggregate data rate of 76 kbit/s - - w h e n the maximum of four SIO boards are installed, eight communications lines are available. The Multibus (IEEE 796) backplane bus serves as a data path between
Voice messaging system Plessey Communication Systems have added an electronic voice messaging system to their IDX digital exchange. The Integrated Voice Messaging System (IVM) is a microprocessorbased digitized voice messaging system designed to increase office productivity by automatically answering routine calls then digitizing and storing voice messages in individual 'mailboxes'. The system allows the user to pick up, play back, save, edit, transfer and create messages while in or out of the office. By entering commands via the touch-tone command structure,
270
the user is able to listen to each message (which is time-stamped with day, hour and minute of receipt), formulate a reply, cancel, save or transfer the message to another mailbox. Messages are played in order of receipt. Additional commands allow the user to broadcast messages to specific groups within the system. E a c h subscriber's mailbox is locked by a unique fourdigit identification code which must follow the user's voice mailbox address. (Plessey Communication Systems Ltd., Justin Manor, 341 London Road, Mitcham, Surrey, UK. -feh 01 646 4141) []
the three modules. A number of programmable configuration options allow the network manager to set such parameters as number and speed of each synchronous link, number and size of buffers and network identification for each Ethernet. The GS/3 also gathers full network statistics to assist in monitoring utilization, throughput, error rates, packet delay and other network measurements. (Bridge Communications Inc. 10440 Bubb Road, Cupertino, CA 95014, USA. Tel: 408 446 2981) []
TV pictures by telephone The Model 250 Transceiver from Colorado Video has been designed to provide visual communications over standard voice-grade dial-up telephone circuits. The transceiver takes a frame of video from a closed-circuit TV camera, digitizes it and converts the frozen picture to a 'slow-scan' television signal suitable for transmission over the telephone. At the receiving location the incoming signal is reconverted into a still image and displayed on a normal TV monitor. The time taken to transmit a complete picture is about 35 s. Slow-scan video is similar in concept to facsimile, but is more flexible in that any subject material which can be viewed by a TV camera can be transmitted. Applications include business or engineering conferencing between two or more locations, person-toperson visual communications, information retrieval, remote sensing, security, remote medical diagnosis and imagery, education and the interconnection of TV signals to computers for image analysis in scientific research. (Brian Reece Scientific Instruments, Unit B, Newspaper House, Faraday Road, Newbury, Berks., UK. Tel: 0635 3282 7) []
computer communications