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Q123324: File Transfer Protocols Supported by HyperTerminal

Article: Q123324
Product(s): Microsoft Windows 95.x Retail Product
Version(s): 
Operating System(s): 
Keyword(s): 
Last Modified: 17-DEC-2000

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The information in this article applies to:

- Microsoft Windows 95 
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SUMMARY
=======

This article contains a brief description of the file transfer protocols
supported by HyperTerminal.

MORE INFORMATION
================

Kermit
------

Kermit is a public domain protocol developed at Columbia University. It is a
sliding-window protocol that supports batch file transfers and has a maximum
block size of 94 bytes. It uses either half or full duplex. Kermit is unique
because it supports either 7-bit or 8-bit data transmission, enabling PC to
mainframe transfers. Kermit uses either CRC or Checksum error correction. Kermit
transfers the filename, date, and size.

X-Modem
-------

X-Modem is a public domain 8-bit, error-checking communications protocol. It is a
single file protocol, has a block size of 128 bytes, and transmits using
half-duplex. The filename, date, and size are not transmitted by X-Modem. You
must provide the name of the file being downloaded. X-Modem uses either CRC or
Checksum error checking, with CRC being the default.

X-Modem-1K
----------

X-Modem-1K is identical to X-Modem except that the block size is 1024 bytes.

Y-Modem
-------

The Y-Modem protocol is virtually the same as X-Modem, with one exception.
Y-Modem uses 1024-byte blocks compared to the X-Modem 128-byte block. Because of
its larger block size, Y-Modem is generally faster than X-Modem on a noise-free
line. On noisy lines, X-Modem may be faster because when an error occurs, the
block must be re-sent. Y-Modem must retransmit a 1024- byte block; with
X-Modem's smaller blocks, less data has to be re-sent.

Y-Modem-G
---------

Y-Modem-G is a variant of the Y-Modem protocol. Y-Modem-G is a streaming protocol
that sends 1024-byte blocks until instructed to stop. Y-Modem-G supports batch
transfers. This protocol does not provide error correction or recovery. If an
error is detected, the transfer is aborted. On a noise- free phone line using
error-correcting modems, Y-Modem-G may be the fastest protocol.

NOTE: Y-Modem-G does not provide error correction or recovery. It is designed
specifically for high-speed error-correcting modems using V.42 or other hardware
error correction.

Z-Modem
-------

The Z-Modem file transfer protocol provides reliable file transfers with complete
end-to-end data integrity. Z-Modem uses 32-bit CRC error correction and a
sliding-window block up to 1024 bytes in length. Z-Modem uses intelligent error
recovery, which automatically decreases block size if the phone line
deteriorates and attempts to increase block size as the phone line improves.
Z-Modem also provides automatic downloads. When the host computer begins
transferring using Z-Modem, the remote computer recognizes this and begins
receiving the download automatically.

Additional query words: upload zmodem ymodem ymodemg ymodem-g xmodem hyperterm

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Keywords          :  
Technology        : kbWin95search kbZNotKeyword3

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