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Calling Method for Alternate Voice Feature

IP.com Disclosure Number: IPCOM000048364D
Original Publication Date: 1982-Jan-01
Included in the Prior Art Database: 2005-Feb-08
Document File: 2 page(s) / 54K

Publishing Venue

IBM

Related People

Bigo, F: AUTHOR [+3]

Abstract

This is a calling method for providing a line multipoint data transmission system with an alternate voice call feature.

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Calling Method for Alternate Voice Feature

This is a calling method for providing a line multipoint data transmission system with an alternate voice call feature.

The system is constructed as shown in the figures. For a call from the Top Monitor side, the following operations are performed: The modem is provided with a function switch which is turned to VOICE position. The Top Monitor then places the Data Transmitter into an idle mode. If the Call Switch is in its NORMAL position, the Tone Transmitter generates a tone which is transmitted to each tributary modem on the receiver side. If the Call Switch is in its SELECTIVE position, then the Top Monitor generates through the Auxiliary Transmitter a special SDLC (Synchronous Data Link Control) message including a predetermined command byte and the address of the multidrop tributary modem station to be called. This address is selected manually, e.g., by the operator through a rotary switch located on the operator's panel. Under the latter circumstances, the call message is sent on the line by the Auxiliary Transmitter at service speed (lower than normal data speed). Consequently, on the tributary modem receiver side, one will therefore either detect a tone or a selective call.

Assuming a tone is detected by the Tone Detector attached to the modem receiver, then the Buzzer is triggered, and during a fixed period of time the modem is placed in idle mode. Otherwise, assuming the tributary modem receiver detects a messa...