Browse Prior Art Database

Data Transmission System

IP.com Disclosure Number: IPCOM000043766D
Original Publication Date: 1984-Sep-01
Included in the Prior Art Database: 2005-Feb-05
Document File: 2 page(s) / 73K

Publishing Venue

IBM

Related People

Yonemochi, K: AUTHOR

Abstract

This article describes a system wherein two devices communicate with a host via a common adapter. The first one of the devices is operable to check the status of the adapter prior to data transmission, while the second device is operable to transmit data without doing such a status check. The adapter is able to suspend the data transmission being conducted between the first device and it when the second device begins the transmission of data. Subsequently, the first device continuously checks the status of the adapter until it is permitted to transmit the suspended data again. By these arrangements, data from the devices are prevented from missing and the time loss in the second device is minimized. In Fig. 1, a device I communicates with an adapter via a cable. The adapter is also connected to a host by a cable.

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Data Transmission System

This article describes a system wherein two devices communicate with a host via a common adapter. The first one of the devices is operable to check the status of the adapter prior to data transmission, while the second device is operable to transmit data without doing such a status check. The adapter is able to suspend the data transmission being conducted between the first device and it when the second device begins the transmission of data. Subsequently, the first device continuously checks the status of the adapter until it is permitted to transmit the suspended data again. By these arrangements, data from the devices are prevented from missing and the time loss in the second device is minimized. In Fig. 1, a device I communicates with an adapter via a cable. The adapter is also connected to a host by a cable. The device I may be a keyboard which functions to perform a key scan operation and check status of the adapter for data transmission to it. A device II may be a keypad which transmits data to the adapter by means of infrared light without doing the status check. The adapter operates as indicated by the flow chart in Fig. 2. At step 21, the adapter sets to a receive enable status wherein it can receive data from any other devices. If data is transmitted from the device II (step 22), the adapter receives it while it inhibits data transmission from the host and the device I (steps 2526), and then the data is transferred to the host...