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Synchronous Microprogram Service Technique for Full Duplex Communications

IP.com Disclosure Number: IPCOM000081453D
Original Publication Date: 1974-Jun-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 62K

Publishing Venue

IBM

Related People

George, DA: AUTHOR [+2]

Abstract

The essential elements of this method are the communication adapter and microprogrammed processor of a terminal control unit.

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Synchronous Microprogram Service Technique for Full Duplex Communications

The essential elements of this method are the communication adapter and microprogrammed processor of a terminal control unit.

In the communications adapter of Fig. 1, data from the demodulator section 10 of the modem is continuously received a bit at a time and deserialized into character form in receive shift register 11 before transfer in parallel to a buffer. Similarly, buffer data is transferred in parallel to a transmit shift register 12 and enters the modulator section 13 of the modem, a bit at a time.

Bit data is moved at different rates, unlike phase, and consequently two separate clock lines 14 and 15 are provided by the modem unit. Transmit clock 15 is determined by an oscillator of the modem, receive clock 14 is determined by an oscillator of the modem at the other end of the communication line and a phase-lock circuit of the local modem. The silo 16 collects transmit data bits at the receive clock rate, and transfers those bits under control of logic 17 at the transmit clock rate in a first-in/first-out manner.

The adapter of Fig. 1 thus shifts and transfers data characters in a synchronous manner. The transmit data is synchronized to the receive data clock. The buffers are being handled at precisely the same rate, thus only one interrupt occurrence is required to simultaneously service both. The logic 17 determines the appropriate time to cause the interrupt. The silo 16 is of...