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Circuit Card Description and Installation
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Appendix A: LAPB Data Link Control
protocol
Contents
This section contains information on the following topics:
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 889
Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 889
Frame structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 890
LAPB balanced class of procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . 891
Commands and responses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 892
Description of procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 893
Introduction
This chapter describes the LAPB Data Link Control protocol used with the
QPC513 ESDI card. The protocol is a subset of the HDLC procedures which
are described in International Organization for Standardization procedures
ISO 3309-1979 (E), ISO 4335-1979 (E) and appendices 1 and 2, and ISO
6256-1981 (E). Refer to these procedures for complete LAPB details.
Applications which use an ESDI port in synchronous mode must conform to
the following requirements.
Operation
Circuit Switch Equipment transfers data to the QPC513 in blocks consisting
of 1 to 128 eight-bit octets. Each block is processed in accordance with the