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Microprocessor Based Auto Call Originator

IP.com Disclosure Number: IPCOM000049722D
Original Publication Date: 1982-Jul-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 3 page(s) / 61K

Publishing Venue

IBM

Related People

Cukier, M: AUTHOR [+2]

Abstract

An auto-call originator (AC0) is a device which is attached ss to a business machine and its associated modem and which calls any number over the public switched network under control of the business machine and then transfers the line to the modem. This article describes a specialized microprocessor in which the call-processing and "watch-dog" tasks are performed independently on an interleaved basis.

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Microprocessor Based Auto Call Originator

An auto-call originator (AC0) is a device which is attached ss to a business machine and its associated modem and which calls any number over the public switched network under control of the business machine and then transfers the line to the modem. This article describes a specialized microprocessor in which the call-processing and "watch-dog" tasks are performed independently on an interleaved basis.

The microprocessor illustrated in the figure performs two independent tasks: the watch-dog task, which consists in checking for errors in the calling process and making sure that the ACO will release the line when such an error occurs., and the call-processing task. These two tasks share a common hardware comprised of: a programmable read-only memory (PROM) in which the various microprogram routines are stored, a decode and control unit (DCU),. a clock and side flip-flop (F/F), and input and output multiplexers. Specific circuits are duplicated (one for each of the two tasks designated by A and B, respectively). This permits the circuits corresponding to one task not to be altered while the other task is being performed. These circuits are: a 4-bit working register (Z)

a status flip-flop (ST)

a 10-bit instruction address register (IAR)

a 4-bit page register (P)

a random-access memory (RAM)

a 4-bit RAM address register (RAR).

The circuits above are selectively enabled by the side flip-flop driven by the clock. The microprocessor performs tasks A and B during odd and even clock periods, respectively.

At power on, the IAR associated with the call-processing task, for example, IAR A, is set to address 0100 000000, and IAR B, associated with the watch-dog task, is set to address 0000 000000. As soon as the watch-dog side decides to abort the telephone call, it forces the calling side to alarm address 1111 000000 which corresponds to the beginning of the abandon call routine. This occurs whatever the address in IAR may be. (see original). Read memory X - The contents of the RAM address XXXX are stored in working register Z. Force X i...