High-speed modems Two high-speed modems have been launched bySE Labs for use as multiplexer links in disc-to-disc data transfer, file dumping and load shedding at transmission speeds of 48-72 kbit/s. The SE35 operates as a conventional base-band modem at either end of the link when transmission is required over telephone lines within a single exchange area. When communication over a greater distance is required, involving wide-band transmission, the SE36 modem to be used in conjunction with the SE35 to translate the data onto a high-frequency carrier for transmission over a group band
Network software A software package for Troubleshooter 800 in-circuit test systems that allows manufacturers to set up a communications network on the factory floor has been announced by Zehntel. The Netcomm software package can link the Troubleshooter 800 to a range of mainframes via an RS232C serial port. In this mode, the 800 emulates a terminal and can be used as an I/O device. Test programs, datalog data and input lists can be uploaded or downloaded to the host computer from the test system, with no disruption of production testing. When Zehntel's Model 110 development system is used as the host, Netcomm can be used to create a communications network between the Model 110, the Troubleshooter 800 and the Troubleshooter 900. Within this network, the 110 can be used to store failure data, to create a program generation input list to transfer to the 800, or to receive program-preparation data from the 900. The network facility also provides a work-in-progress management
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channel. Data transmission is at fixed rates of 48, 56, 60, 64 or 72 kbit/s. Both modems are equipped with a CCITT V.35 interface. Using a typical line, the SE35 can transmit data at 48 kbit/s over a distance of about 16 kin. The SE36 is suitable for wide-band transmission over satellite, microwave or coaxial links. In addition, the SE36 contains its own interface circuits, which enable it to operate on its own in applications where an SE35 is not required. (SE Labs (EMI) Ltd., Spur
Road, North Feltham Trading Estate, Feltham, Middx. TW14 OTD, UK. Tel: 01 890 1477) []
system with statistical quality control, and allows real-time process monitoring. Eight data transfer rates are available, from 110-9 600 bit/s, with either 6, 7 or 8 bit coding. (Zehntel, 2625 Shadelands Drive, Walnut Creek, CA 94598, USA. Tel: 415 932 6900, Tx: 910 385 6300) []
19 200 bit/s modem
Protocol controller The first part of a two-chip system that can operate as a bus controller is now available in the UK. The HS-3273 is the first of the MIL STD 1553B protocol controllers, and can handle the functions of a remote terminal. Operating as a dumb remote terminal, the 3273 is first programmed by its host through I/O control transfers. Then, as a bus interface unit, the device can carry out data transfers to and from host memory via DMA, stimulated by commands from the serial databus. As a controller, the 3273 is first programmed by its host, and can then execute the program code. The second chip for the system, the HS-3274, is still in the design stage. Using the two chips in controller bus interface unit designs is expected to reduce component and host assistance requirements.
(Harris Semiconductor, 145 Farnham Road, Slough, Berks., UK. Tel: 0753 34666) []
Computer typesetting
A modem that can handle data rates of 2 400-19 200 bit/s over distances of up to 37 km has been launched by Codex. The 8250 Local Distribution Service Unit can be used on both low-grade public circuits and private copper cable. It is based on a differential diphase modulation technique and an automatic equalizer. Point-to-point or multipoint operation is provided, along with local and remote unattended diagnostics, a range of status indicators and dedicated on-board DC power supply. A high-density nest version is also planned. (Codex
A communications interface system from Randall Typographic is claimed to reduce the production cost of typeset manuals by as much as 45%. The interface translates microcomputer commands into typesetting codes and effectively removes the need for compositor intervention and proof reading. A customer can key his copy into a microcomputer and store it on a floppy disc, along with the typesetting codes. The copy and codes can then be transferred to a digital typesetter via the interface system. The only decisions to be made are where the page endings should fall and what the page headings should be.
(UK) Ltd., 105/107 Lansdowne Road, Croydon CRO 2BN, UK. Tel: 01 680 8507, Tx: 946847) []
(Randall Typographic Ltd., 10 Barley Mow Passage, London, W4 4PH, UK. Tel: 01 994 6477, Tx: 8811418)
computer communications