Zhone 3920Plus Bedienerhandbuch PDF herunterladen (Seite 327)

H-13920-A2-GH30-40 October 1998

Synchronous Data Compression

Overview H-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Synchronous Data Format H-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SDC Algorithm H-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

DTE and DCE Frames H-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SDC User Interface H-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Data Synchronization H-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Flow Control Method H-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Tuning SDC Efficiency H-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

DTE Configuration H-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Modem Configuration H-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SDC Negotiation H-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Overview

The Paradyne proprietary Synchronous Data Compression (SDC) feature allows an increase of

throughput in data transmission, and has an error correcting procedure so that transmitted data is

less sensitive to channel disturbances.

The ITU-T recommendations, V.42bis, and V.42 have data compression and error correcting (EC)

procedures for DCEs connected to asynchronous DTEs. These procedures form the basis for

Paradyne’s SDC feature.

Within the SDC feature, two DTEs can exchange data via a synchronous protocol (Figure H-1)

while the DCE provides the new synchronous data compression and error correction functions

(Figure H-2). The synchronous data from the local DTE, after compression, is inserted into DCE

frames which are sent to the remote DCE. Inverse operations then occur at the remote DCE.

SYNCHRONOUS

DTE

DCE

19.2 kb/s

DCE

9.6 kb/s

SYNCHRONOUS

DTE

19.2 kb/s

SYNCHRONOUS PROTOCOL

495-14784-01

Figure H-1. Sample DTE Exchange of Data via Synchronous Protocol and SDC

1 2 ... 322 323 324 325 326 327 328 329 330 331 332 ... 353 354

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