duplicate processing, sequence number checking, message transfer, system message preparation and a SWl FT certified protocol. (Wang (UK) Ltd., 1000 Great West Road, Brentford, A4iddx TW8 9HL, UK. Tel: 01-568 4444, Telex: 295795) [ ]

PC access to multivendor token rings

A PC-DOS terminal emulator and file- transfer program that allows IBM PCs to communicate with multivendor equipment over an IBM Token Ring (IEEE 802.5) local area network has been introduced by Bridge Communications.

The Tokenterm software works on PCs attached directly to the Token Ring using the Token Ring Adapter card available from IBM.

The Tokenterm software, together with Bridge's CS/I-TR Token Ring Communications Server, permits the PC user to access computer resources via the CS/I-TR, as well as run IBM network applications.

Tokenterm has a built-in emulator for DEC VTI00 and V-I-52 terminals and a program interface to support other emulations.

For third-party emulation programs, Tokenterm replaces the IBM PCs Bios Interrupt 14H interface routines with its own program interface. The interrupt 14H calls are redirected away from the PC's serial port through the Tokenterm virtual circuit, so that emulation programs can be written for alternative terminals.

Tokenterm consists of the XNS (Xerox Network Systems) high-level protocol set with a menu-driven terminal emulation and file-transfer application residing above the protocols. It permits PCs to access asynchronous devices, SNA hosts, modem pools, and asynchronous host ports (e.g. HP, DG, DEC, etc.) through Bridge's CS/I-TR. PC-to-host file transfers are supported using both the text and XMODFM file-transfer protocols. (Bridge Communications Ltd., Lloyds Bank Building, 56 High Street, Marlow-on-Thames, Bucks SL7 1AJ, UK.) []

Videotex gateway for IBM users

A videotex gateway that will enable customers, sales personnel and the general public using videotex terminals to directly access a company's IBM mainframe via the Prestel network, has been launched by Brown's Operating System Services.

The VPM/VlP package consists of Brown's Viewdata Page Manager (VPM) software and its associated frame editor, the Viewdata Information Provider (VlP). VPM allows mainframe users to construct private videotex systems both easily and at a very low cost. The VlP frame editor allows construction of display

and response frames in videotex formats. The number of frames is limited only by mainframe disc capacity.

In addition to the normal videotex features, an alphagraphics facility is provided which allows the information providers to use large alphanumeric characters built up from alphamosaic graphics characters. VPM and VlP can run under MVS/ VTAM and DOS/VSE, with or without VTAM. (Browns Operating Systems Services Ltd., St Agnes House, Cresswell Park, Blackheath, London SE3 9RD, UK. Tel: 01-852 3299, Telex: 839149) []

High-speed fibre-optic LAN

A high-speed fibre-optic local area network has been launched which conforms to the FDDI (Fibre Distributed Data Interface) standard. This standard has been defined under the auspices of the ANSI (American National Standards Institute) X3T9.5 working group.

The Systems Finex network from Fibronics is a dual fibre, high bandwidth, 100 Mbit/s counter-

rotating token-ring system. System Finex will connect heterogeneous workstations with mainframe computers, and will also interconnect existing Ethernet networks through bridges and gateways.

System Finex conforms to all seven layers of the ISO model. (Fibronics Ltd., Telford House, Hamilton Close, Basingstoke, Hants RG21 2YT, UK. Tel: (0256) 468794, Telex: 859892) []

Long distance data communication

The Megastream/T1 Master from Able Computer will enable high speed, long distance data communi- cation by private or public telephone line.

The network adaptor converts 1 Mbit/s data stream to megastream using CCITT G.703 and G.704 formats, and superimposes HDLC (high level data link control) onto megastream connections. Communi- cations sent through the adaptor have an upper limit of 1.2 Mbit/s. Approximately 340 kbit of bandwidth support the detection of network functions, the change of data formats

required to conform to megastream and CRC detection and framing. Users will be data-rate independent as well as time-slot independent.

The DTE (data terminal equipment) interface of Megastream/T1 Master uses incoming bit streams as data and does not attempt to decode or modify data content. Because the DTE bit stream runs at 1 Mbit/s and the DS-1 bit stream runs at 2.048 Mbit/s, bit stuffing is used to match bit rates. (Able Computer House, 287 London Road, Newbury, Berks RG73 3QJ, UK. Tel: (0635) 32125 Telex: 848715 ABLE G) []

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