Browse Prior Art Database

Supervisory Response in Data Processor Controlled Printer

IP.com Disclosure Number: IPCOM000044976D
Original Publication Date: 1983-Jan-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Hayes, RL: AUTHOR

Abstract

The present system provides an expedient wherein a two-bit indicator is used to determine whether or not a supervisory response is necessary during an optional response cycle in an SDLC (Synchronous Data Link Control) loop communication interface between a host data processor and a printer. An optional response is made when one or two conditions exist. The determination of these two conditions is performed via a test on the two bits of the indicator which are conveniently in the same status byte. For example, in the present system wherein a data processor is controlling a printer, a supervisory response is transmitted during an optional response cycle if one of the following conditions is true and no explicit response command has been received: 1.

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Supervisory Response in Data Processor Controlled Printer

The present system provides an expedient wherein a two-bit indicator is used to determine whether or not a supervisory response is necessary during an optional response cycle in an SDLC (Synchronous Data Link Control) loop communication interface between a host data processor and a printer. An optional response is made when one or two conditions exist. The determination of these two conditions is performed via a test on the two bits of the indicator which are conveniently in the same status byte. For example, in the present system wherein a data processor is controlling a printer, a supervisory response is transmitted during an optional response cycle if one of the following conditions is true and no explicit response command has been received: 1. A Receiver Ready (RR) to Receiver Not Ready (RNR) transition

has occurred and has not been reported to the primary

station.

2. An RNR to RR transition has occurred and has either not been

reported to the primary station or not acknowledged by the

primary station.

The determination of these two conditions is performed via tests on two bits in the same status byte. One bit (RECEIVER STATUS) denotes the current status of the secondary station's (i.e., printers) receiver. If the bit is a "one", then the secondary station has buffers available. If the bit is a "zero", then no buffers are available. The other bit (ACKNOWLEDGED STATUS) denotes whether the current status has bee...