73D2248A View Datasheet(PDF) - TDK Corporation

Part Name

Description

Manufacturer

73D2248A

MNP5, V.42bis Datacom Modem Device Set

TDK Corporation 

PROTOCOLS

Microcom Networking Protocol (MNP)

MNP4 is a protocol offering error control while MNP5

offers data compression. Data to be transmitted is

broken into blocks of varying sizes, depending on

line conditions, and sent to the remote modem along

with a 16-bit Cyclic Redundancy Check (CRC) word.

If the algorithm used to derive the CRC word at the

transmitter does not produce an identical word when

exercised on the received data, a line error is

assumed, and the block is repeated. Data

compression is obtained by transmitting a short set

of characters for a longer redundant set. At the

receiver, the short string is replaced with the longer

string that it represented, and the data stream is

returned to its original state.

73D2248A/2348A

MNP5, V.42bis Datacom

Modem Device Set

CCITT V.42 AND V.42BIS

The CCITT has ratified a set of protocols which

operate in a manner similar to MNP. MNP4

corresponds to V.42 while MNP5 corresponds with

V.42bis. Greater efficiency is offered, but the

tradeoff is a larger memory space requirement.

MNP5 requires an 8K buffer, while V.42bis requires

32K. Data files which show compression ratios

approaching 2:1 with MNP5 may show ratios of

nearly 4:1 with V.42bis.

ADDITIONAL INFORMATION

The TDK Semiconductor Corporation 73D2248/2348

Design Manual defines the AT commands. Please

contact your local TDK Semiconductor Corporation's

sales office for a copy of the TDK Semiconductor

Corporation's Protocol Design Manual.

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