Browse Prior Art Database

AUTOSYNCHRONIZING SHORT HAUL DATA CONCENTRATOR WITH HANDSHAKING

IP.com Disclosure Number: IPCOM000005553D
Original Publication Date: 1984-Apr-01
Included in the Prior Art Database: 2001-Oct-15
Document File: 3 page(s) / 119K

Publishing Venue

Motorola

Related People

Steve Bramblett: AUTHOR

Abstract

This circuit is intended to improve digital data communications occurring over asynchronous channels such as might occur between a computer and a terminal. Most terminals are designed to communicate at a 9600 baud rate in a full duplex asychronous mode which puts severe distance requirements between the computer and its terminals. This circuit will allow up to eight terminals to communicate at 9600 baud full duplex over a single 26 gauge twisted-pair wire over distances up to 2 kilometers. As a bonus this design not only allows local handshaking but it also allows a remote handshake to be used with the terminals which has not been practical for modulated data transmission schemes.

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c&j MOTOROLA Technical Developments Volume4 April 1984

AUTOSYNCHRONIZING SHORT HAUL DATA CONCENTRATOR WITH HANDSHAKING

by Steve Bramblett

   This circuit is intended to improve digital data communications occurring over asynchronous channels such as might occur between a computer and a terminal. Most terminals are designed to communicate at a 9600 baud rate in a full duplex asychronous mode which puts severe distance requirements between the computer and its terminals. This circuit will allow up to eight terminals to communicate at 9600 baud full duplex over a single 26 gauge twisted-pair wire over distances up to 2 kilometers. As a bonus this design not only allows local handshaking but it also allows a remote handshake to be used with the terminals which has not been practical for modulated data transmission schemes.

CIRCUIT DESCRIPTION

    This system comprises two distinct pieces of hardware separated by a twisted-pair wire. The first unit attaches to eight data channels at the computer's end. This unit is the master unit and is so dubbed because the intermediate data link between the two units fs controlled by the master through timing generated there. The second unit, the slave, is attached to the terminals and it is designed to respond to the master's timing.

   Both units utilize the Motorola Universal Digital Loop Transceiver (UDLT) and the Motorola Data Set Interface (DSI). The DSI takes any asynchronous data up to 9600 baud and converts it to a 8 kilobit per second synchronous format for the KILT. The DSI also performs the reverse process and since only one channel can be handled by the DSI, eight are needed for each unit. The UDLT is capable of providing two way digital data communications at 80 kllobits per second in each direction and in so doing is basically an 80 kilobit per second differential phase shift key modem.

   The timing control of the master unit is based on a frame concept. A frame is 125 microseconds long so8000framesoccureach secondand theyaredefined bytheMSI orframesync pu1se.A totalof 10 bitsof information is transferred in each direction for every frame, 8 of which are actual data and two are signa...