Browse Prior Art Database

Remote Concentrator Distributor

IP.com Disclosure Number: IPCOM000093770D
Original Publication Date: 1966-Feb-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 4 page(s) / 79K

Publishing Venue

IBM

Related People

Gomez, A: AUTHOR [+5]

Abstract

A centrally located computer, not shown, communicates with this remotely located multiplexer via a full-duplex high-speed transmission line. The multiplexer distributes the information received from the high-speed line to a plurality of low-speed lines.

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Remote Concentrator Distributor

A centrally located computer, not shown, communicates with this remotely located multiplexer via a full-duplex high-speed transmission line. The multiplexer distributes the information received from the high-speed line to a plurality of low-speed lines.

The computer transmits a continuous train of telegraph characters over the high-speed line. Each character train consists of a sync character followed by a unique character slot associated with the first low-speed line, followed by a character slot associated with a second low-speed line etc. Thus, each low- speed line is assigned a particular character slot in sequence. Each character slot contains ten bits but the quantity used can vary depending upon the telegraph code employed. In each character slot, one bit is used to indicate that a data character is present one bit is used for control information and the remaining eight bits define the data character.

Subset A is located at the computer and provides a clock line for shifting data out of a shift register not shown and for stepping a bit counter not shown, located at the computer. At every count of ten bits the contents of a buffer register located at the computer are transferred to the shift register the buffer register is reset and a character counter at the computer is incremented. This causes a new character to be placed in the data buffer register. The count in the character counter designates the low-speed line to which the next character is to be sent and assures that each character is put in the proper time slot. When the character count reaches twenty-eight, a predetermined sync character is inserted into the buffer at the computer. This sync character is then transmitted over the full-duplex line to subset B. The remote multiplexer, described below, recognizes the sync character, synchronizes with it and returns a similar sync character in the character train transmitted to subset A. A sync check is performed at both ends each time a sync character is due.

In the example shown a full-duplex 2400 bit per second, high-speed line communicates between subsets A and B and thirty low-speed lines, operating at
56. 8 bits per second are served by multiplexer scanner 16. Two lines 29 and 30 are permanently looped together for test purposes. Free-running clock 10 provides clock pulses 1...20. Cycle counter 12 is driven by the output 20 of clock 10 to provide clock cycle counts 1...4. Address counter 14 provides counts 0...30 for synchronizing low-speed scanner 16. Transmit Operation.

Data received from subset B is shifted into XMIT shift register 20. A sync character is decoded by sync decoder circuit 22. At clock time 15, sync trigger 24 is turned on. Every time a bit is fed into register 20 a bit counter 26 is stepped. When the bit counter reaches a count of nine i.e., after ten bits have been received an output from Or 28 causes the contents of register 20 to be transferred to XMIT buffer re...