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Browse Prior Art Database

Parallel Data Transmission Scheme

IP.com Disclosure Number: IPCOM000044320D
Original Publication Date: 1984-Dec-01
Included in the Prior Art Database: 2005-Feb-05
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Dishon, Y: AUTHOR [+2]

Abstract

This parallel data transmission scheme allows the high speed transmission of data between parallel channels and control units over long distances by solving the bit-skewing problem. The data is placed into the transmitter in byte form. A self- clocking transmission on each bus-line follows. At the receiving end, the data is decoded, buffered into shift registers, and delivered at the destination in byte form again. The length of the shift registers depends on the maximum transmission bit-skew. In earlier implementations, channel-control unit communications were carried out over byte-wide unidirectional buses with acknowledgment signals exchanged at every byte transfer.

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Parallel Data Transmission Scheme

This parallel data transmission scheme allows the high speed transmission of data between parallel channels and control units over long distances by solving the bit-skewing problem. The data is placed into the transmitter in byte form. A self- clocking transmission on each bus-line follows. At the receiving end, the data is decoded, buffered into shift registers, and delivered at the destination in byte form again. The length of the shift registers depends on the maximum transmission bit-skew. In earlier implementations, channel-control unit communications were carried out over byte-wide unidirectional buses with acknowledgment signals exchanged at every byte transfer. This very inefficient, in terms of throughput, transmission scheme was considerably improved by data streaming, a technique which allows the transmission of an entire block of data without waiting for acknowledgment after each byte transfer. However, data streaming is also throughput-limited because of bit-skewing problems at every byte transfer. Under the present data streaming scheme, the capture of bytes at the receiving end is done by means of a clocking signal which is transmitted in parallel with each byte. The rate of data transmission depends on the amount of bit-skewing which, in turn, is a function of the distance between channel and control unit. As a result of the bit- skewing problem, channel-control unit transmissions are limited in practice to 3 Mbytes/sec over maximum distances of 400 ft. It is these shortcomings of existing channel-control unit parallel transmission schemes that the disclosed scheme eliminates. DESCRIPTION OF THE INVENTION The disclosed parallel data transmission scheme consists of two parts, i.e., a transmitter and a receiver, as shown in the figure. The transmitter consists of an 8-bit wide buffer, 8 data encoding circuits for each bit of the byte and control logic. Each dat...