Browse Prior Art Database

Printer Control Interface Between Host Data Processor and Word Processing System Printer

IP.com Disclosure Number: IPCOM000041477D
Original Publication Date: 1984-Feb-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Mueller, MW: AUTHOR

Abstract

In the present-day information processing environment, the host data processor may provide its printed output on a word processing system printer which is emulating a data processing system printer, such as the IBM 3287. In such an emulation the connection is via a high speed asynchronous half duplex coaxial link between the printer being emulated and the controller or multiplex unit for the host data processor. The protocol used on the link requires a large number of simple data transactions which require immediate response. The word processor emulation responds to these transactions without the intervention of the microprocessor associated with the word processing system. This is accomplished by a parallel data routing method in the control module which will be described hereinafter.

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Printer Control Interface Between Host Data Processor and Word Processing System Printer

In the present-day information processing environment, the host data processor may provide its printed output on a word processing system printer which is emulating a data processing system printer, such as the IBM 3287. In such an emulation the connection is via a high speed asynchronous half duplex coaxial link between the printer being emulated and the controller or multiplex unit for the host data processor. The protocol used on the link requires a large number of simple data transactions which require immediate response. The word processor emulation responds to these transactions without the intervention of the microprocessor associated with the word processing system. This is accomplished by a parallel data routing method in the control module which will be described hereinafter. This parallel data routing method allows the control logic to meet the astringent timing requirement of the link interface without requiring the loading of the word processing system on which the emulation is taking place. Before the data is processed by the control module, it must be decoded and deserialized; likewise, the response must be encoded and serialized. This is accomplished in the Link Control Modules (LCM) shown in Fig.
1. One other function of the LCMs is the synchronization of the data to the timing of the logic. From this synchronization logic, several timing signals or state clocks are derived. These states divide the time between successive words of serial data into six equal time slices. For convenience, the slices will be numbered sequentially zero to five, with state zero being ju...