British Telecom has also introduced an X21 circuit switching gateway for IBM Personalikes that it developed at its Martlesham Laboratories in Suffolk. It comes in the form of a plug-in board containing a Telecom-designed HDLC chip and an 8088 standard processor. The product, which will not be available until the end of 1987, will be bundled with Merlinword. It is compatible with its Integrated Digital Access, IDA, pilot version of Integrated Services Digital Network, ISDN and provides high-speed file transfer between workstations. The CCITT I420 version of ISDN recommends that two 64Kbps channels are used for speech and data and one 16Kbps channel for control signals. Telecom’s IDA uses only one 64Kbps channel for voice and data and one 8Kbps channel for control. Telecom is also showing the networked version of dBase III, at UKP795.
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