Frequently Asked Questions (and answers) about Kermit software.
 From comp.protocols.kermit.misc and elsewhere...

Most recent update: Tue Feb  7 09:25:04 1995
-------------------------------------------------------------------------
CONTENTS:

   DIRECTORY: How to contact us.

   1. Q: WHERE DO I GET DOCUMENTATION?
         A: Here's a list of manuals and how (and why) to get them.

   2. Q: WHY IS KERMIT SO SLOW COMPARED TO ZMODEM?
         A: It isn't if you tune it for speed; here's how.

   3. Q: MY BACKSPACE KEY DOESN'T WORK!
         A: Here's why, and how to fix it.

   4. Q: HOW DO I USE KERMIT OVER TRUMPET WINSOCK?
         A: Sorry, you don't, here's why.

   5. Q: HOW TO TRANSFER FILES THROUGH A 3270 PROTOCOL CONVERTER?
         A: Here's a brief tutorial.

   6. Q: WHERE IS THE KEY MAP FOR 3270 EMULATION?
         A: This is completely site-dependent, here's why.

   7. Q: CAN I MAKE MS-DOS KERMIT USE COM3, COM4?
         A: Yes.

   8. Q: MS-DOS KERMIT PATCHES DON'T SEEM TO TAKE EFFECT.
         A: Several possible reasons for this, and how to fix.

   9. Q: I CAN TRANSFER TEXT FILES BUT NOT BINARY FILES.
         A: Several possible reasons for this, and how to fix.

  10. Q: BINARY FILES ARE CORRUPTED AFTER TRANSFER.
         A: Then they probably were not transferred in binary mode.

  11. Q: WHY DOESN'T THE HANGUP COMMAND WORK FOR ME?
         A: Various reasons, and how to make it work.

  12. Q: HOW CAN I MAKE THE {DIAL, REDIAL} COMMAND KEEP TRYING?
         A: It's easy, here's how.

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DIRECTORY:

  World-Wide Web:
        http://www.columbia.edu/kermit/

  ftp:  kermit.columbia.edu
        This is the definitive source for Kermit software
        on the Internet.  Other Kermit archives or "mirror sites"
        are not necessarily complete, accurate, or up to date.

  Newsgroups:
        comp.protocols.kermit.announce - Moderated
        comp.protocols.kermit.misc     - Unmoderated

  LISTSERV:
        I$KERMIT@CUVMA.BITNET or CUVMA.CC.COLUMBIA.EDU - Submissions
        LISTSERV@CUVMA.BITNET or CUVMA.CC.COLUMBIA.EDU - Subscriptions

  KERMRSV:
        KERMSRV@CUVMA.BITNET or CUVMA.CC.COLUMBIA.EDU - Files
        (Send e-mail with text HELP to get started.)

  E-mail:
        kermit@columbia.edu (not an FTP mail server!)

  Post: Kermit Distribution
        Columbia University Academic Information Systems
        612 West 115th Street
        New York, NY  10025-7221
        USA

  Fax:  +1 212 663-8202  or  +1 212 662-6442

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FREQUENTLY ASKED QUESTIONS:

Most questions are already answered in the published documentation.  Reading
the appropriate manuals (in conjunction with online release notes) will get
you started, answer most of your questions, and will let you get the most out
of your Kermit software: maximize the performance, write scripts to automate
your communications tasks, and so on.  The Kermit effort is entirely
self-supporting, and proceeds from sales of these manuals is our primary
source of funding.  So please do purchase the manuals.

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(1) WHERE TO GET KERMIT MANUALS

MS-DOS Kermit, full-featured communications software for IBM and
compatible PCs with DOS or Windows, is documented in:

    Christine M. Gianone, Using MS-DOS Kermit, Second Edition, Digital
    Press / Butterworth-Heinemann, Woburn, MA, 1992, 345 pages, ISBN
    1-55558-082-3.  Packaged with version 3.13 of MS-DOS Kermit for the
    IBM PC, PS/2, and compatibles on a 3.5-inch diskette.  In computer
    and book stores, or order direct from Columbia University or from
    Digital Press.

A German-language edition is also available:

    Christine M. Gianone, MS-DOS Kermit, das universelle
    Kommunikationsprogramm, Verlag Heinz Heise, Hannover, Germany
    (1991), 414 pages.  Packaged with version 3.12 of MS-DOS Kermit for
    the IBM PC, PS/2, and compatibles on a 5.25-inch diskette,
    including German- language help files.  Deutsch von Gisbert W.
    Selke.  ISBN 3-88229-006-4.

And a French-language edition:

    Christine M. Gianone, Kermit MS-DOS mode d'emploi, Deuxieme
    edition, Heinz Schiefer & Cie., Versailles (1993), 406 pages.
    Packaged with version 3.11 of MS-DOS Kermit for the IBM PC, PS/2,
    and compatibles on a 5.25-inch diskette.  Adaption francaise: Jean
    Dutertre.  ISBN 2-901143-20-2.

There is also a Japanese book about MS-DOS Kermit, concentrating on the
NEC PC9801:

    Hirofumi Fujii and Fukuko Yuasa, MS-Kermit Nyumon, Computer Today
    Library 6, Saiensu-Sha Co., Ltd., publishers (1993), 160 pages.
    ISBN 4-7819-0669-9 C3355 P1854E.

C-Kermit 5A, full-function communication software for UNIX, VMS, OS/2,
AOS/VS, OS-9, Apollo Aegis, the Commodore Amiga, and the Atari ST is
documented in:

    Frank da Cruz and Christine M. Gianone, "Using C-Kermit", Digital
    Press / Butterworth-Heinemann, Woburn, MA, 1993, 514 pages, ISBN
    1-55558-108-0.  In computer and book stores, or order direct from
    Columbia University or from Digital Press.

A German-language edition is also available:

    Frank da Cruz und Christine M. Gianone, C-Kermit--Einfuhrung und
    Referenz, Verlag Heinz Heise, Hannover, Germany (1994).  ISBN
    3-88229-023-4.  Deutsch von Gisbert W. Selke.

The Kermit File transfer protocol is specified in the following book,
which also includes tutorials on computers, file systems, data
communications, and using Kermit:

    Frank da Cruz, Kermit, A File Transfer Protocol, Digital Press /
    Butterworth-Heinemann, Worburn, MA, 1987, 379 pages, ISBN
    0-932376-88-6.  In computer and book stores, or order direct from
    Columbia University or from Digital Press.

Kermit software for more than 400 different computers and operating
systems is available from Columbia University.  Contact Columbia for a
free Kermit software catalog.

ENGLISH-LANGUAGE KERMIT BOOKS:

   1. In computer and book stores, or order direct from the publisher,
      Digital Press / Butterworth-Heinemann with MasterCard, Visa, or
      American Express:

          +1 800 366-2665     (Woburn, MA office for USA & Canada)
          +44 993 58521       (Rushden, England office for Europe)
          +61 2 372-5511      (Chatswood, NSW office for Australia & NZ)
          +65 220-3684        (Singapore office for Asia)

   2. From Columbia University:

          Kermit Development and Distribution
          Columbia University Academic Information Systems
          612 West 115th Street
          New York, NY  10025  USA
          Tel.  +1 212 854-3703
          Fax.  +1 212 663-8202
          E-Mail: kermit@columbia.edu

      Domestic and overseas orders accepted.  Add $10 US PER BOOK for
      shipping outside of North America.  Orders may be paid by
      MasterCard or Visa, or prepaid by check in US dollars.  Add $35
      bank fee for checks not drawn on a US bank.  Price includes
      shipping.  Do not include sales tax.  Quantity discounts are
      available.  Single-copy US prices (in US dollars):

          Using MS-DOS Kermit  . . . . . . . . . . . . . . . . .$ 36.95
          Using C-Kermit . . . . . . . . . . . . . . . . . . . .$ 36.95
          Kermit, A File Transfer Protocol . . . . . . . . . . .$ 32.95
          All three  . . . . . . . . . . . . . . . . . . . . . .$ 85.00

GERMAN-LANGUAGE KERMIT BOOKS:

        MS-DOS Kermit, das universelle Kommunikationsprogramm: DM 79,00
        C-Kermit--Einfuhrung und Referenz: . . . . . . . . . . DM 88,00

        Verlag Heinz Heise GmbH & Co. KG
        Helstorfer Strasse 7
        D-30625 Hannover, GERMANY
        Tel.  +49 (05 11) 53 52-0
        Fax.  +49 (05 11) 53 53-1 29

FRENCH:  Kermit MS-DOS Mode d'Emploi:  . . . . . . . . . . .  FF 495,00

        Heinz Schiefer & Cie.
        45 rue Henri de Regnier
        F-78000 Versailles, FRANCE
        Tel.  +33 39 53 95 26
        Fax.  +33 39 02 39 71

JAPANESE:  MS-Kermit Nyumon: . . . . . . . . . . . . . . . . .  1,800 Y

        Saiensu-Sha Co., Ltd.
        Abe-toku Building
        2-4 Kanda-suda cho, Chiyoda-ku
        Tokyo 101, JAPAN
        Tel.  +81-3-3256-1091

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(2) WHY IS KERMIT SO SLOW COMPARED TO ZMODEM?

Path: news.columbia.edu!usenet
From: fdc@fdc.cc.columbia.edu (Frank da Cruz)
Newsgroups: comp.protocols.kermit.misc
Subject: Re: [HELP] Slow Kermit Transfer ?!
Date: 19 Sep 1994 14:15:42 GMT
Organization: Columbia University
Lines: 153

In article <35jrgsINNdq2@newsman.csu.murdoch.edu.au>
anson@csuvax1.csu.murdoch.edu.au (Binh Anson) writes:
> I used Kermit 3.13 for my PC, my modem has a speed of 14.4 K, but I found
> that the downloading rate from the mainframe to my PC was still very slow!
> I tried Telix with SZ (Z-Modem Protocol), and it was very fast compared to
> Kermit. Is there a way to accelerate Kermit transfer ?
> 
Yes.

But first, welcome to comp.protocols.kermit.misc.  This is the first
day of operation of this unmoderated newsgroup.  I hope it will prove
beneficial to all Kermit users.

To answer your question, somewhat longwindedly, since this Question is
Asked so Frequently :-) ...

Zmodem is optimized for speed on the assumption that it has a clear 8-bit
transparent channel with no blockages (small buffers, etc), and so, out of
the box, when it works it goes fast.  The tradeoff is that it often does
not work at all, in which case you have to configure it in various ways --
escaping of control characters, changing window size, etc.  In some cases
it can't be made to work at all, either because of the nature of the
connection, or because of one or both of the computers on the two ends.

Kermit, on the other hand, is configured to work -- i.e. transfer files --
out of the box, even under hostile conditions.  By default, it does not 
assume that control characters pass through transparently, nor that large
buffers are available.  It does not even assume a full-duplex connection.
The tradeoff is speed.

In a perfect world, there would be no tradeoffs, but the world is far from
perfect.  7-bit transmission is still extremely common, small buffers are
very common, even in modern terminal servers and other communications
processors, flow control is rarely implemented correctly and effectively,
telephone lines are still noisy, and we still have a bewildering array
of communication methods needed for accessing different kinds of hosts and
services.  Most PCs are still shipped with non-buffered UARTs; many PCs
have interrupt conflicts, noisy buses, etc; many modern modems are buggy.
The list goes on.  This is by way of demonstrating that Kermit's default
tuning is not crazy, and goes a long way towards explaining its justified
reputation for dependability.

Unfortunately, because of the tradeoffs necessary to achieve its
reliability, Kermit has a reputation for slowness:

  Yes, Kermit transfers are slow if you use the default tuning.

However, you can make Kermit go as fast as the communication path will permit
by changing a few parameters.  But first, here are some general principles
that apply to all communications software:

 1. Ensure that you have an effective means of flow control enabled at
    every juncture along the communication path (this applies to any file
    transfer protocol).  For example, when using high-speed,
    error-correcting modems, you should use some form of hardware flow
    control, most commonly RTS/CTS.  You have to tell the software to use
    it, AND you have to tell the modem to use it too -- if the flow
    control methods of the PC and the modem do not agree, then data will
    be lost.

 2. If your modem is capable of data compression, use it.  Fix the
    interface speed of the software to four times the connection speed if
    possible -- e.g. for a V.32bis 14400 bps connection, use an interface
    speed of 57600, or else the modem's compression capacity is likely to
    be wasted.

 3. On network connections (e.g. TCP/IP), it is usually best to turn off
    flow control entirely, because the underlying networking method
    supplies fully effective flow control.

Now, to make Kermit go fast, follow these steps:

 1. Use real Kermit software, not the many shareware and commercial
    packages, most of whose Kermit protocol implementations lack the
    performance features listed below and/or the means for the user to
    control them.

 2. Use long packets.  Kermit's default packet length is 94.  You can
    increase it to a theoretical maximum of 9024.  Give the following
    command to the file receiver:

      SET RECEIVE PACKET-LENGTH 2000  ; (or other length)

    The longer you make the packets, the more efficient the file transfer
    will be... IF IT WORKS.  If you make packets longer than some buffer
    somewhere along the line, and effective flow control is lacking, the
    transfer might not work.  Also, the longer the packet, the greater
    the chance it will be hit by noise, and the longer it takes to
    retransmit.  A good starting value to try is 1000.

 3. On full duplex connections, use sliding windows.  Sliding windows
    allow packets to be transmitted in a continuous stream, rather than
    "stop and wait" style.  The command is:

      SET WINDOW 4 ; (or other number)

    The maximum is 32 (or less, depending on the implementation).  Give
    this command to *both* Kermit programs.

For text files and uncompressed binary files, this should give you very
good performance -- efficiencies in the 85%-100% range.  For compressed
files, and certain other types of binary files, you can squeeze out
another 20-25% efficiency by telling Kermit not to prefix a given list of
control characters.  A typical sequence might be:

  SET CONTROL UNPREFIX ALL  ;  Unprefix all control characters.
  SET CONTROL PREFIX 0 1 13 129 141 ...  ; Add back prefixes for these.

This might require some trial and error because there is no way that a
communication software program can know what characters are safe and
which ones are not on a particular connection.  For example, you might be
going through an X.25 PAD where Ctrl-P will pop you back to the PAD
prompt.  Or you might be going through a TELNET terminal server where
Ctrl-] or Ctrl-^ will pop you back to the terminal server prompt.  Or the
connection might be using Xon/Xoff flow control, and sending Ctrl-S as a
data character might freeze the connection.

If you take all of these steps, using optimal packet lengths, window
sizes, and unprefixing, you should achieve transfer rates comparable to,
and often better than, the Zmodem implementations that you find in Telix,
Procomm, and similar shareware and commercial packages; for example, on a
V.32bis/V.42/V.42bis connection, RTS/CTS flow control, no parity, 57600
bps interface speed:

  Typical text files:        3500 cps (characters per second)
  Uncompressed binary files: 2400 cps (e.g. PC KERMIT.EXE)
  Compressed files:          1600 cps (e.g. ZIP files)

These figures come from Kermit News #5, June 1993, which is available via
anonymous ftp from kermit.columbia.edu, directory kermit/e, file
newsn5.txt (ASCII) or newsn5.ps (PostScript).  Also see newsn4.txt (.ps)
for a detailed discussion of long packets and sliding windows.

Kermit software is available via anonymous ftp to kermit.columbia.edu
[128.59.39.2], directory kermit and its subdirectories.  There are
literally hundreds of different Kermit programs for *almost* every machine
and operating system imaginable.  The most widely used Kermit programs are:

 . MS-DOS Kermit 3.14 for DOS and Windows.
   No, this is not a native Windows application, but yes, this
   is the software we recommend for Windows.
   File: kermit/bin/msvib.zip.

 . C-Kermit 5A(190) for UNIX, VMS, OS/2, AOS/VS, the Commodore Amiga, etc.
   UNIX: kermit/bin/cku190.tar.Z.
   VMS: Get kermit/b/ckvaaa.hlp, read it, take it from there.
   Others: Get kermit/b/ckaaaa.hlp, read it, take it from there.

 . IBM Mainframe Kermit-370 4.3 for VM/CMS, MVS/TSO, CICS, and MUSIC.
   kermit/b/ik*.*.

- Frank

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 3. MY BACKSPACE KEY DOESN'T WORK!

From: fdc@watsun.cc.columbia.edu (Frank da Cruz)
Newsgroups: comp.protocols.kermit.misc
Subject: Re: [?] Backspace key says, "^?"
Date: 7 Jan 1995 21:26:44 GMT
Organization: Columbia University
Lines: 122

In article <D201pG.DMB@indirect.com>, Jim Monty <monty@indirect.com> wrote:
>DISCLAIMER:  I've looked for the answer to the following question in
>             _Using MS-DOS Kermit_ and in the documentation included
>             with MS-DOS Kermit 3.13.  I either couldn't find the
>             answer or didn't understand it if I did.
>
Thank you for consulting the documentation.

>I'm using MS-DOS Kermit 3.13 on an i80386SX machine running MS-DOS 6.0, 
>using a 14,400 bps Zoom VFP V.32bis modem.  Kermit is set for VT220 
>terminal emulation and is using the Latin1 character set and code page 
>CP437.  I've not mucked with much in the initialization files, so you may 
>assume that any other parameters are still set to the "factory" defaults.
>
>Alas, the question:  In some online environments, my backspace key behaves
>as one would expect it to.  In others, hitting the backspace key results
>in either (1) nothing happening, or (2) the characters "^?"  appearing on
>the screen.  I can, however, use Ctrl-H in these situations.  In these
>exact same online environments (e.g., vi insert mode when connected to my
>dial-up UNIX shell account) under analagous circumstances, the other
>terminal emulator that I use, Telemate Version 3.12, does not behave this
>way.  The backspace key functions as a destructive backspace. 
>
>I presume that the change I need to make to my MS-DOS Kermit 
>configuration is a simple one, but I can't figure it out.  And I've never 
>really wanted to bother to spend a lot of time trying to figure it out 
>myself.  (I want the magic straight from the wizards' minds.)  Thanks, in 
>advance, for taking the time to help me.
>
>Jim Monty, Kermit Cheerleader at Arthur Andersen LLP
>
Well, Jim, I think it's finally time to classify this as a Frequently
Asked Question and add it to the FAQ (kermit.columbia.edu:kermit/FAQ.TXT).

As you have discovered, different hosts and applications use different
characters (or sequences) for destructive backspace.  The terminal
emulator, Kermit or otherwise (including Telemate -- if its backspace key
works for you in all circumstances, I think that's just a stroke of luck),
has no way of knowing what host or application you are using, and
therefore no way of knowing what to send when you press the Backspace key.

Of course, Kermit's Backspace key must send *something* "out of the box",
so it uses one of the several most likely destructive backspace values,
and in fact the one that is defined in ASCII to be destructive backspace,
namely Rubout, also known as Delete or DEL, character number 127, which
sometimes is displayed as "^?".  Lest anyone believe this is a frivolous
choice, I quote from American National Standard X3.4-1977, Section 5.1,
Control Characters:

  0/8 BS (Backspace).  A one-active-position format effector that moves
  the position backward on the same line.

  7/15 (DEL). A character used primarily to erase or obliterate an
  erroneous or unwanted character...

In cases where the default does not work, Kermit lets you redefine the
Backspace key (or any other key) to send whatever you want it to send (or
to take any other actions) with the SET KEY command.

The SET KEY command has two operands: a unique identifier for a key or key
combination, called a scan code, and the value or action to be assigned to
the key.  Scan codes are written with a preceding backslash (\).  The scan
code for the Backspace key is \270.  The default definition for this key
is \127, meaning the character whose numeric value is 127, i.e. DEL.

You can find out a key's scan code by consulting Table I-9 in the manual
(pages 285-288), or by giving the SHOW KEY command to Kermit and then
pressing the desired key or key combination.

Now, as you have discovered, some applications use Ctrl-H -- ASCII BS
(Backspace) -- for destructive backspace.  Consulting the ASCII table on
page 275, you see that the ASCII code for BS is 8.  So to make PC's
Backspace key send BS instead of DEL, give this command:

  SET KEY \270 \8

If you use Kermit only to connect to hosts and services that use BS for
destructive backspace, then you can put this command in your MSCUSTOM.INI
file, and it will take effect automatically every time you start Kermit.

But some people (like yourself) switch between different hosts and/or
services that expect different characters or sequences for destructive
backspace.  You can, of course, give Kermit the appropriate command
every time you switch from one to another:

  SET KEY \270 \8    ; Backspace sends BS

or:

  SET KEY \270 \127  ; Backspace sends DEL

or you can use the macros that are already defined in MSKERMIT.INI for
this.  In version 3.14, for example, we have macros with names like
VAX and IBM.  The VAX macro sets things up (including the Backspace key)
for communicating with VAXes and VAX-like systems, and that means, among
other things, setting the Backspace key to send DEL.  The IBM macro, on
the other hand, is used for communicating with IBM mainframes in linemode,
where BS is used.

You can use these macros as they are, or you can write your own macros
based upon them and add them to your MSCUSTOM.INI file.  To use a macro,
just type its name at the MS-Kermit> prompt.

Suppose, for example, you normally access two different systems: a BBS
(which uses 8-bit characters, ANSI terminal emulation, and BS) and a UNIX
system (which uses 7-bit characters, VT220 emulation, and DEL), and these
items need to be changed when you switch between the two.  You could write
two macros such as these:

  define bbs set term byte 8, set term type ANSI, set key \270 \8
  define unix set term byte 7, set term type vt220, set key \270 \127

And then each time you want to use the BBS, you just type "bbs" at the
MS-Kermit> prompt, and each time you want to access the UNIX system,
you type "unix".

Of course, you could take this process even further, and turn the BBS and
UNIX macros into complete connection-establishment and login scripts,
following the directions in Chapter 14 of the manual, on script
programming.

- Frank

-------------------------------------------------------------------------
(4) HOW DO I USE KERMIT OVER TRUMPET WINSOCK?

Date: Sun, 8 Jan 95 13:27 EST
To: ....
From: kermit@columbia.edu
Subject: Re: Using Kermit with Trumpt Winsock

> I have an internet connection (SLIP) using Trumpet Winsock to establish
> the connection to the server under windows.  I'd like to use kermit at
> that point to telnet to my company's computer.  I've filled in the IP
> addresses in my custom file, but when I run kermit, and try to telnet,
> I get the message:
> 
>   Cannot attach to an Ethernet Packet Driver....
> 
> Can you give me an idea of what I'm doing wrong?
> 
Presently, it can't be done.  The rule for DOS, Windows, and similar PC
operating systems is:

  ONE APPLICATION PER PROTOCOL PER NETWORK BOARD

This applies also to serial ports being used as if they were network
boards, e.g. via SLIP.

Now, Trumpet Winsock is using (i.e. registered for) the TCP protocol on
your "network board".  Thus, when you try to activate Kermit's own
built-in TCP/IP networking, it finds that it can't register TCP because
TCP is already registered.  Thus it "Cannot attach to ... Packet Driver".

One might think it would be possible, then, to tell Kermit to "use"
Winsock.  But Winsock TCP/IP stacks are strictly for pure Windows (and NT)
programs, not for DOS programs.  MS-DOS Kermit is a "Windows-aware" DOS
program, but a DOS program nevertheless; it runs from the DOS prompt and
within DOS emulator boxes in various operating systems, and cannot access
Winsock.  If you want to make a TCP/IP connection with Kermit when Winsock
is running, you have to unload Winsock and use Kermit's own built-in
TCP/IP capability directly over an Ethernet- or SLIP-class packet driver
or an ODI driver.

LATER ADDENDUM:

Not much is known about this yet, but there is evidently a new shim, written
by Dan Lanciani (who also wrote ODIPKT), an NDIS3-to-real-mode packet driver
VXD, that multiplexes the WIN32 IP stack with the DOS packet-driver-based IP
stack.  We don't know anything about it, including where to get it or what
the licensing terms are.

-------------------------------------------------------------------------
(5) HOW TO TRANSFER FILES THROUGH A 3270 PROTOCOL CONVERTER?

From: fdc@watsun.cc.columbia.edu (Frank da Cruz)
Newsgroups: comp.protocols.kermit.misc
Subject: Re: Kermit File Transfer and tn3270
Date: 16 Jan 1995 16:46:18 GMT
Organization: Columbia University
Lines: 169

In article <173276AEB.BDESIMON@uga.cc.uga.edu>,
Bert DeSimone <BDESIMON@UGA.CC.UGA.EDU> wrote:
>Gotta figure this has come up before.  We are evaluating a terminal server
>that supports tn3270.  No problem using MS-Kermit to connect to the terminal
>server and connect via tn3270 to an IBM mainframe.  However, file
>transfers (either invoking server on the mainframe or not) always fail.
>Connecting through this same terminal server to the same mainframe
>through a 7171 presents *no* problem with file transfer.  (BTW: I don't
>have to be using tn3270 on a terminal server; file transfers with Kermit
>using tn3270 on a Unix host fail the same way).
> 
>I am speculating that the mainframe Kermit must send a transparent mode
>sequence, ordinarily processed by the protocol converter, that is causing 
>the problem.
> 
One of the major strengths of the Kermit protocol is its ability to
transfer files with IBM mainframes over a wide variety of connection
types, and there is an excellent Kermit software program for the IBM
mainframe, which is available for VM/CMS, MVS/TSO (and ROSCOE), CICS, and
MUSIC.  The current version is 4.3.0, with version 4.3.1 in beta test.

All of the Kermit books and manuals ("Kermit, A File Transfer Protocol",
"Using MS-DOS Kermit", "Using C-Kermit", and the IBM mainframe Kermit
online manuals) describe the process(es) in some detail.  Here is a brief
summary.

Half-duplex (local-echo), line-at-a-time connections are generally handled
by the "ibm" macro that is built in to MS-DOS Kermit and C-Kermit, which
performs the following protocol-related settings:

  set local-echo on
  set parity mark
  set flow none
  set handshake xon

Full-screen sessions go through a 3270 terminal emulator.  This can reside
anywhere between the client software (such as MS-DOS Kermit) and the
mainframe.  For the past 10 or 20 years, the most common place to find the
3270 emulator was on a special purpose "protocol converter": a box that
has serial lines on one side and a connection to the mainframe on the
other.  This box generally works by tricking the mainframe into thinking
it is a "control unit" with multiple 3270 terminals attached, and at the
same time tricking the terminals into thinking they are communicating with
a "normal" ASCII character-at-a-time host.  The box converts between 3270
data streams and ASCII terminal (e.g. VT100) conventions.  This includes
ASCII/EBCDIC character-set conversion, cursor positioning and screen
painting, and keystroke interpretation.

As you can imagine, all of these conversions would normally have a
disastrous effect on Kermit protocol packets, and also upon any other type
of data that has to be transmitted "as is", without conversion, such as
graphics terminal directives.  Thus, many protocol converters support a
"transparent mode", that allows the mainframe host to command them to turn
off their conversion functions, and at a later time, turn them back on.

When everything works as planned, the only Kermit commands required for
going through the protocol converter are:

  set flow xon/xoff ; (usually)
  set parity even   ; (or other)

Everything else corresponds to the normal Kermit defaults (remote echo,
no "handshake", etc).

Unfortunately, the method for entering and leaving transparent mode
differs from one 3270 emulation product to another.  Ideally, there are
two components: (1) the identification phase, in which the mainframe
software issues a special instruction that causes the protcol converter to
respond in a unique (but harmless) way; and (2) the actual enter- and
exit-transparent-mode directives.

IBM Mainframe Kermit needs to know which kind of transparency, if any, is
used by the protocol converter so it can be put into transparent mode at
the beginning of packet protocol and taken out of it upon return to
interactive command mode.  There are several ways that mainframe Kermit
can go about this.  First, you can use the SET CONTROLLER command to tell
it which style of transparency is used by the protocol converter.  Second,
mainframe Kermit can be set up by the system administrator to always use a
particular style.  Third, it can attempt to "autodiscover" the controller
type by issuing various types of identification queries and checking the
results.  The third method is not very reliable, however, since many types
of protocol converters fail to respond to these queries even when they do
implement a particular style of transparency.

Nowadays, special-purpose protocol converters are giving way to general
purpose terminal and compute servers that include a "tn3270" function.
tn3270 is a special kind of TELNET program that also performs 3270
emulation, and requires that the mainframe be on a TCP/IP network and have
a TN3270 server.  Here are two examples:

 1. UNIX tn3270.  Most UNIX systems come with a tn3270 program that lets
    you make a full-screen connection to an IBM mainframe.  Once you have
    made the connection, you should be able to start Kermit on the
    mainframe, give it a SEND, RECEIVE, or SERVER command, escape back to
    your terminal emulator (e.g. MS-DOS Kermit), and transfer files
    without any special settings.  If you have trouble with this, then:

     . Ask mainframe Kermit to "show controller".  If it doesn't say
       Series/1, then tell it to "set controller series1".

     . Try using shorter packets.  The maximum length that can pass
       through the protocol converter might be less than what you are
       trying to use.  A typical maximum value might be 1700.

     . Tell one or both Kermit programs to "set parity space".

 2. Cisco terminal server tn3270.  Current releases of Cisco terminal
    server software include a tn3270 feature that is supposed to permit
    Kermit transfers, but it has bugs.  Sometimes these bugs can be worked
    around by using the methods listed in (1) above and specifying VERY
    short packets, like 30 or 40 bytes.  Sometimes they can't be worked
    around at all.  A future release of Cisco software (probably 10.3)
    will include new tn3270 software that implements Series/1-style
    transparency correctly, and allows Kermit transfers of both text and
    binary files in both directions using packet lengths up to about 1900
    (or whatever the total screen size is).

If you try all of these workarounds with your terminal server and still
get failed transfers, make packet logs and/or debug logs in both Kermit
programs to find out what the terminal server is delivering to each Kermit
program, and report the misbehavior to your terminal server vendor.

For further information about specific protocol converters and how to
configure IBM Mainframe Kermit for them, please read the ik0aaa.hlp file
that comes with IBM Mainframe Kermit.

Finally, it is possible to transfer files through a 3270 fullscreen
connection even when 3270 emulator can't be put into transparent mode at
all.  You can read about this in the C-Kermit update notes file
(ckcker.upd) and the MS-DOS Kermit update notes files (KERMIT.UPD).
Quoting from the latter:

"Doomsday Kermit" (DDK) techniques allow file transfer with IBM mainframes
through 3270 protocol converters that do NOT support transparent mode, to be
used in conjunction with IBM Mainframe Kermit's SET CONTROLLER FULLSCREEN
command on VM/CMS, MVS/TSO, or CICS.  MS-DOS Kermit 3.13 or later and IBM
Mainframe Kermit 4.2.3 or later required.  Commands:
	
  SET PARITY EVEN	 ; Or whatever
  SET FLOW XON/XOFF	 ; Or whatever
  SET SEND START 62	 ; Greater-than sign
  SET RECEIVE START 62	 ; Ditto
  SET BLOCK BLANK-FREE-2 ; New block-check type
  SET HANDSHAKE NONE

BLANK-FREE-2 is a new block-check type, exactly like type 2, except encoded
to never contains blanks.  Give IBM Mainframe Kermit the following commands:

  SET CONTROLLER FULL
  SET SEND START 62
  SET RECEIVE START 62
  SET BLOCK BLANK-FREE-2
  SET HANDSHAKE 0

Doomsday Kermit file transfers are not as reliable as regular Kermit protocol
transfers, and they are much slower.  Use this method only as a last resort;
that is, only when you can't get a transparent-mode fullscreen connection or
a linemode connection to the mainframe.

(end quote)

And beyond finally: in the future, we expect to add 3270 emulation to the
Kermit software itself, so you will be able to make tn3270 connections
directly from Kermit to the mainframe without having to go through a
"black box" for the conversion.  Of course, Kermit software will handle
transparency correctly (and automatically).  (And no, I can't estimate
when built-in 3270 emulation will be available.)

- Frank

-------------------------------------------------------------------------
(6) WHERE IS THE KEY MAP FOR 3270 EMULATION?

Real 3270 terminals have all sorts of keys that regular ASCII terminals
(and PCs and Macintoshes and UNIX workstations, etc) do not have.

A big part of the job of a 3270 protocol converter is to convert between
ASCII keystrokes (including escape sequences) and 3270 keys such as PA1
through PA3 and PF1 through PF24.

The administrator of the 3270 protocol converter creates the mapping.
So in order to make a 3270 key map for Kermit, you first have to find out
what the mapping in the protocol converter is, and then assign the ASCII
values (characters or sequences) that correspond to each 3270 key to the
desired PC (or Mac, etc) key.

It is the responsibility of each site administrator to document the key
mappings used by its protocol converters.  Once you know the ASCII values
that correspond to each 3270 key, then it's easy to create Kermit key
bindings.

For example, suppose the 3270 "cursor left" function (left arrow) is mapped
to ASCII Ctrl-B (ASCII character 2).  Then in MS-DOS Kermit you would:

  SET KEY \4427 \2

where \4427 is the scan code of the PC's (gray) left arrow key, and \2 is
the code for the ASCII value of the Ctrl-B character.

-------------------------------------------------------------------------
(7) CAN I MAKE MS-DOS KERMIT USE COM3, COM4?

From: fdc@watsun.cc.columbia.edu (Frank da Cruz)
Newsgroups: comp.protocols.kermit.misc
Subject: Re: COM3 available in 3.14?
Date: 20 Jan 1995 15:48:20 GMT
Organization: Columbia University

In article <1995Jan19.232004.8689@midway.uchicago.edu>,
Cal Lott <cal@gsbux1.uchicago.edu> wrote:
>I was simply wondering if version 3.14 (or any earlier) could
>address COM3 and above. 
>
A frequently asked question.  The short answer: Yes.

The medium answer: COM3 and above have no standard address or IRQ,
hence communications software (Kermit or anything else) can't always
find them, in which case you have to specify the address and IRQ,
using a sequence like:

  SET COM3 \x3e8 5
  SET PORT COM3

(You need both commands, in the order shown.)

The long answer: Read section 6 of the KERMIT.BWR file on your MS-DOS
Kermit 3.14 diskette.

- Frank

-------------------------------------------------------------------------
(8) MS-DOS KERMIT PATCHES DON'T SEEM TO TAKE EFFECT.

Since the release of MS-DOS Kermit 3.14, there have been persistent reports
that patches don't seem to "stick".  That is, after giving a PATCH command,
the patch level is still reported as 0.  This can happen if the patch file is
transferred to the PC from a UNIX system in binary mode, so the lines end
with LF rather than CRLF -- DOS does not recognize the line boundaries and
therefore Kermit does not see valid patches.  Cure: make sure each line ends
with CRLF.  Fix it in an editor, or re-transfer the file in text mode.

Also, remember there is no longer a need to rename the patch file to
MSKERMIT.PCH.  Since there are now three different Kermit executables, there
must be three corresponding patch files.  For version 3.14, these are:

  MSR314.PCH  -- For full-featured KERMIT.EXE
  MSRM314.PCH -- For "medium-size" KERMITE.EXE
  MSRL314.PCH -- For "Kermit Lite" KERLITE.EXE

Notice that each patch file includes the version number as part of its
name.  This allows you to run different versions of Kermit without confusion
about patching.

-------------------------------------------------------------------------
(9) I CAN TRANSFER TEXT FILES BUT NOT BINARY FILES

Here are the causes (and cures) listed in decreasing order of likelihood:

 1. You are going through a terminal server or other type of connection
    (telnet, rlogin, etc) that chops off the 8th bit.  Kermit can't tell
    that this is happening (as it can with devices that add even, odd,
    or mark parity), so you have to tell it.  The command is:

      SET PARITY SPACE

 2. You have used the SET CONTROL CONTROL UNPREFIX command to unprefix
    one or more control characters that are not safe.  Tell Kermit to:

      SET CONTROL PREFIX ALL

    and see if it works.  If so, you'll have to home in on the offender(s).

-------------------------------------------------------------------------
(10) BINARY FILES ARE CORRUPTED AFTER TRANSFER

Kermit transfers files in text mode by default.  This means that record
formats and character sets are likely to be converted.  You can tell Kermit
to skip all conversions and transfer the file literally, as-is, with the
command:

  SET FILE TYPE BINARY

Normally, it is sufficient to give this command to the FILE SENDER before
giving it the SEND command.  But there are some exceptions to this rule:

 1. One or both Kermits do not support "Attribute packets" (or they are
    disabled).  This is true of many of the commercial and shareware
    Kermit implementations.  Cure: tell BOTH Kermits to use binary mode.

 2. You are using some combination of C-Kermit 5A(190) or later, MS-DOS
    Kermit 3.14 or later, or IBM Mainframe Kermit 4.3.1 or later in
    client server mode.  In this case, it is the CLIENT's file type setting,
    rather than the file sender's, that prevails.  Cure: tell the CLIENT
    to SET FILE TYPE BINARY, or to be extra sure, tell them both.

 3. You are sending the file from VMS C-Kermit, which is unique among
    Kermit programs in its ability to automatically switch between text
    and binary mode based on the file's characteristics.  VMS C-Kermit
    ignores SET FILE TYPE BINARY and SET FILE TYPE TEXT when sending
    files, and instead uses binary mode if the file's record format is
    Fixed, and text mode otherwise.  However, some binary files, notably
    VMS ZIP files, are stored using a "text-style" record format
    (Stream_LF), so Kermit sends them in text mode.  You can override
    this by telling it to SET FILE TYPE IMAGE.
-------------------------------------------------------------------------
(11) WHY DOESN'T THE HANGUP COMMAND WORK FOR ME?

On network connections, Kermit's HANGUP command executes the appropriate
network protocol for closing the connection, and this should always work.

On serial connections, the HANGUP commands turns off the computer's DTR
(Data Terminal Ready) signal for a period of time.  According to the standard
that governs modem signals, this action is supposed to make a modem hang up
the phone call.  If it doesn't:

 1. Your modem has been configured to "Ignore DTR".  This setting is
    available on most Hayes-compatible modems, either on a physical switch
    (such as Configuration Switch 1 on the Hayes 1200) or as a command (&Dx
    on Hayes 2400 and later, and compatibles).  In many cases, "Ignore DTR"
    is the factory setting.  If you want your modem to obey the DTR signal,
    then you should set the switch appropriately, or give the command AT&D2.
    The actual syntax of the command might vary among different brands and
    models of modems, so consult your modem manual for details.

 2. Your cable or connector has DTR "hotwired high", meaning that the DTR
    wire is jumpered to some other signal that is always high (on).  If this
    is not what you desire, you should replace your cable with a standard
    modem cable.

To work around these problems in Kermit, without actually fixing the
underlying cause, you can use a macro that escapes back to the modem's command
processor and gives it the command to hang up.  Such a macro is predefined for
you in the MS-DOS Kermit 3.14 initialization file, MSKERMIT.INI:

  ; ATHANGUP macro.  Use this if regular HANGUP command doesn't do the trick.
  def ATHANGUP sleep 1,out +++,sleep 1,out ath0\13

You can use exactly the same technique in C-Kermit.  It assumes your modem is
Hayes compatible, and that your modem's "escape character" is plus-sign; if it
isn't, change the plus-signs appropriately.

In MS-DOS Kermit and OS/2 C-Kermit, you can even assign execution of this
macro to the "hot key" of your choice, for example:

  set key \315 {\Kathangup}  ; Assign ATHANGUP macro to the F1 key

-------------------------------------------------------------------------
(12) HOW CAN I MAKE THE {DIAL, REDIAL} COMMAND KEEP TRYING?

In MS-DOS Kermit, the DIAL command is defined in the MSKERMIT.INI file, and it
does indeed retry the call several times.  REDIAL is also a macro, which
simply invokes the DIAL macro with the number most recently dialed; hence it,
too, tries the number several times.  If you want to change the number of
times that the DIAL macro tries, or the conditions under which it retries, or
the interval between tries, simply edit the DIAL macro definition in
MSKERMIT.INI.

In C-Kermit, DIAL and REDIAL are built-in commands, each of which dials once.
If you want them to dial more than once, you can define macros as follows.
Put the definitions in your .mykermrc or CKERMOD.INI file.  Here are some
samples:

  define mydial dial \%1, while fail { redial, sleep 30 }

and/or:

  define myredial redial, while fail { redial, sleep 30 }

Embellish as desired.

-------------------------------------------------------------------------
