Browse Prior Art Database

Microprogram Control of Line Simulation

IP.com Disclosure Number: IPCOM000076845D
Original Publication Date: 1972-May-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 3 page(s) / 48K

Publishing Venue

IBM

Related People

Dougherty, ED: AUTHOR [+3]

Abstract

In today's teleprocessing systems, it is essential that any malfunctions which occur in the communications equipment be quickly isolated and repaired. One of the major problems in this area is the determination of whether the problem exists in the communication adapter or in the communication line. In an attempt to improve the fault isolation in this area, most communication adapters include the capability to "wrap" the transmit logic to the receiver logic. This facilitates the testing of the adapter's internal data paths and controls.

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Microprogram Control of Line Simulation

In today's teleprocessing systems, it is essential that any malfunctions which occur in the communications equipment be quickly isolated and repaired. One of the major problems in this area is the determination of whether the problem exists in the communication adapter or in the communication line. In an attempt to improve the fault isolation in this area, most communication adapters include the capability to "wrap" the transmit logic to the receiver logic. This facilitates the testing of the adapter's internal data paths and controls.

However, an important area of the usual adapters left out by this method is the logic means included to interface to the communications line and intended to detect line malfunctions and maintain the integrity of the adapter.

Testing in this area can be improved by the addition of control line and intended to detect line malfunctions and maintain the integrity of the adapter.

Testing in this area can be improved by the addition of control logic which provides for the simulation of communication line signals, which are time-wise and hardware-wise independent of the basic adapter. It is important to stress the fact that the simulation hardware operates asynchronously with the basic adapter, as this is the true relationship of the line with the adapter. With the advent of microprogramming used as control in new control units, simulating the communication line facility now becomes more practical.

Fig. 1 is a fragmentary schematic logic diagram that depicts a typical application of an improved line simulation technique. The transmit bit latch 3 is a device which provides the source of the serial bit stream to the modulator facility. The state of this latch is shown controlled from two independent sources, namely, the DIAG MODE line 5 and the...