ICS1893 Rev B 9/10/99

September, 1999

16

Chapter 4

Overview of the ICS1893

ICS1893 Data Sheet - Release

Copyright © 1999, Integrated Circuit Systems, Inc.

All rights reserved.

Chapter 4

Overview of the ICS1893

The ICS1893 is a stream processor. During data transmission, it accepts sequential nibbles from its MAC

(Media Access Control)/Repeater Interface, converts them into a serial bit stream, encodes them, and

transmits them over the medium through an external isolation transformer. When receiving data, the

ICS1893 converts and decodes a serial bit stream (acquired from an isolation transformer that interfaces

with the medium) into sequential nibbles. It subsequently presents these nibbles to its MAC/Repeater

Interface.

The ICS1893 implements the OSI model’s physical layer, consisting of the following, as defined by the

ISO/IEC 8802-3 standard:

The ICS1893 is transparent to the next layer of the OSI model, the link layer. The link layer has two

sublayers: the Logical Link Control sublayer and the MAC sublayer. The ICS1893 can interface directly to

the MAC and offers multiple, configurable modes of operation. Alternately, this configurable interface can

be connected to a repeater, which extends the physical layer of the OSI model.

The ICS1893 transmits framed packets acquired from its MAC/Repeater Interface and receives

encapsulated packets from another PHY, which it translates and presents to its MAC/Repeater Interface.

Note:

As per the ISO/IEC standard, the ICS1893 does not affect, nor is it affected by, the underlying

structure of the MAC/repeater frame it is conveying.