Microsoft KB Archive/87962

= Works: Communications Module File Transfer Protocols =

Article ID: 87962

Article Last Modified on 11/16/2006

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APPLIES TO


 * Microsoft Works 3.0 for MS-DOS
 * Microsoft Works 2.0 Standard Edition
 * Microsoft Works 2.0a
 * Microsoft Works 3.0 Standard Edition
 * Microsoft Works 4.5 Standard Edition
 * Microsoft Works 4.5a
 * Microsoft Works 4.0 Standard Edition
 * Microsoft Works 4.0a
 * Microsoft Money 2000 Business & Personal Edition

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This article was previously published under Q87962



SUMMARY
This article describes the four binary file transfer protocols available with Microsoft Works.

The following file transfer protocols are available in the Works Communications module:


 * XModem
 * YModem
 * ZModem
 * Kermit



MORE INFORMATION
During binary transfers, data from a file is transmitted in packets (small groupings of information sent sequentially to the COM port). Each packet contains a block of information from the file you are transferring, as well as added information from the sending protocol to help trap sending or receiving errors.

XModem
XModem transfers files in packets of 128 to 1024 bytes in size. In most cases, it uses all eight bits of the packet bytes as data bits, which precludes any parity error checking. The error checking method used by XModem is either Cyclic Redundancy Check (CRC) or the older Checksum method. The Checksum method is used if the remote computer does not support CRC. (Works supports the CRC method.)

YModem
Like XModem, this protocol transfers files using packets of 128 to 1024 bytes. Works uses this protocol only with 1024-byte packets. Like XModem, YModem can use either the CRC or Checksum error schemes; Works supports the CRC error scheme. YModem differs from XModem in that it uses a batch transfer, (that is, it transfers more than one file in a full transmission, rather than one file at a time).

ZModem
ZModem is widely accepted as one of the quickest transfer protocols available. It transfers packets ranging in size from 128 to 1024 bytes; this protocol dynamically changes the packet size depending on whether it detects any sending or receiving errors. This makes it extremely efficient, even on poor connections. It also utilizes a 16 or 32 bit CRC error checking scheme and has the ability to resume previously suspended transfers where it left off.

Kermit
Kermit is mainly used when you are transferring files to or from mainframes or over remote network connections. This protocol makes use of 64-byte packets. Either seven or eight of the transmitted bits are used as data bits, which allows parity checking in certain cases. Kermit is extremely slow but very reliable.

