ckcbwr.txt

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   certain German modem treats any dial string that contains the letter
   "s" as a command to fetch a number from its internal list, and replies
   OK to the ATD command, which is normally not a valid response except
   for partial dialing. To avoid this situation, use:

  lookup xyzcorp
  if success dial

  6.2. The Carrier Signal

   Remember: In many C-Kermit implementations (depending on the
   underlying operating system -- mostly Windows, OS/2, and
   System-V-based UNIX versions, and in C-Kermit 7.0, also VMS), you
   can't CONNECT to a modem and type the modem's dialing command (like
   "ATDT7654321") manually, unless you first tell C-Kermit to:

  SET CARRIER-WATCH OFF

   This is because (in these implementations), the CONNECT command
   requires the modem's Carrier Detect (CD) signal to be on, but the CD
   signal doesn't come on until after dialing is complete. This
   requirement is what allows C-Kermit to pop back to its prompt
   automatically when the connection is hung up. See the description of
   SET CARRIER-WATCH in "Using C-Kermit".

   Similarly, if your dialed connection drops when CARRIER-WATCH is set
   to AUTO or ON, you can't CONNECT back to the (now disconnected) screen
   to see what might have happened unless you first SET CARRIER-WATCH
   OFF. But sometimes not even SET CARRIER-WATCH OFF will help in this
   situation: certain platforms (for example Unixware 2.1), once carrier
   drops, won't let the application do i/o with the device any more. In
   that case, if you want to use the device again, you have to CLOSE it
   and OPEN it again. Or you can have Kermit do this for you
   automatically by telling it to SET CLOSE-ON-DISCONNECT ON.

  6.3. Dialing and Flow Control

   Don't SET FLOW RTS/CTS if your modem is turned off, or if it is not
   presenting the CTS signal. Otherwise, the serial device driver can get
   stuck waiting for this signal to appear.

   Most modern modems support RTS/CTS (if they support any hardware flow
   control at all), but some computers use different RS-232 circuits for
   the same purposes, e.g. DTR and CD, or DTR and CTS. In such cases, you
   might be able to make your computer work with your modem by
   appropriately cross-wiring the circuits in the cable connector, for
   example the computer's DTR to the modem's RTS, and modem's CD to the
   computer's CTS. HOWEVER, C-Kermit does not know you have done this. So
   if you have (say) SET FLOW DTR/CD, C-Kermit will make no attempt to
   tell the modem to use RTS/CTS. You probably did this yourself when you
   configured the modem.

  6.4. The Dial Timeout

   If it takes your call longer to be completed than the timeout interval
   that C-Kermit calculates, you can use the SET DIAL TIMEOUT command to
   override C-Kermit's value. But beware: the modem has its own timeout
   for completing the call. If it is a Hayes-like modem, C-Kermit adjusts
   the modem's value too by setting register S7. But the maximum value
   for S7 might be smaller than the time you need! In that case, C-Kermit
   sets S7 to 0, 255, or other (modem-specific) value to signify "no
   timeout". If Kermit attempts to set register S7 to a value higher than
   your modem's maximum, the modem will say "ERROR" and you will get a
   "Failure to initialize modem" error. In that case, use SET DIAL
   TIMEOUT to override C-Kermit's calculation of the timeout value with
   the highest value that is legal for your modem, e.g. 60.

  6.5. Escape Sequence Guard Time

   A "TIES" (Time-Independent Escape Sequence) modem does not require any
   guard time around its escape sequence. The following text:

  +++ATH0

   if sent through a TIES modem, for example because you were uploading
   this file through it, could pop the modem back into command mode and
   make it hang up the connection. Later versions of the Telebit T1600
   and T3000 (version LA3.01E firmware and later), and all WorldBlazers,
   use TIES.

   Although the probability of "+++" appearing in a Kermit packet is
   markedly lower than with most other protocols (see the [54]File
   Transfer section below), it can still happen under certain
   circumstances. It can also happen when using C-Kermit's TRANSMIT
   command. If you are using a Telebit TIES modem, you can change the
   modem's escape sequence to an otherwise little-used control character
   such as Ctrl-_ (Control-Underscore):

  AT S2=31

   A sequence of three consecutive Ctrl-_ characters will not appear in a
   Kermit packet unless you go to extraordinary lengths to defeat more
   than a few of Kermit's built-in safety mechanisms. And if you do this,
   then you should also turn off the modem's escape-sequence recognition
   altogether:

  AT S48=0 S2=255

   But when escape sequence recognition is turned off, "modem hangup"
   (<pause>+++<pause>ATH0<CR>) will not work, so you should also SET
   MODEM HANGUP RS232-SIGNAL (rather then MODEM-COMMAND).

  6.6. Adaptive Dialing

   Some modems have a feature called adaptive dialing. When they are told
   to dial a number using Tone dialing, they check to make sure that
   dialtone has gone away after dialing the first digit. If it has not,
   the modem assumes the phone line does not accept Tone dialing and so
   switches to Pulse. When dialing out from a PBX, there is almost always
   a secondary dialtone. Typically you take the phone off-hook, get the
   PBX dialtone, dial "9" to get an outside line, and then get the phone
   company's dialtone. In a situation like this, you need to tell the
   modem to expect the secondary dialtone. On Hayes and compatible
   modems, this is done by putting a "W" in the dial string at the
   appropriate place. For example, to dial 9 for an outside line, and
   then 7654321, use ATDT9W7654321:

  SET PBX-OUTSIDE-PREFIX 9W

   (replace "9" with whatever your PBX's outside-line prefix is).

  6.7. The Busy Signal

   Some phone companies are eliminating the busy signal. Instead, they
   issue a voice message such as "press 1 to automatically redial until
   the number answers, or...". Obviously this is a disaster for modem
   calls. If your service has this feature, there's nothing Kermit can do
   about it. Your modem will respond with NO CARRIER (after a long time)
   rather than BUSY (immediately), and Kermit will declare the call a
   failure, rather than trying to redial the same number.

  6.8. Hanging Up

   There are two ways to hang up a modem: by turning off the serial
   port's DTR signal (SET MODEM HANGUP-METHOD RS232-SIGNAL) or sending
   the modem its escape sequence followed by its hangup command (SET
   MODEM HANGUP-METHOD MODEM-COMMAND). If one doesn't work, try the
   other. If the automatic hangup performed at the beginning of a DIAL
   command causes trouble, then SET DIAL HANGUP OFF.

   The HANGUP command has no effect when C-Kermit is in remote mode. This
   is on purpose. If C-Kermit could hang up its own controlling terminal,
   this would (a) most likely leave behind zombie processes, and (b) pose
   a security risk.

   If you DIAL a modem, disconnect, then SET HOST or TELNET, and then
   HANGUP, Kermit sends the modem's hangup command, such as "+++ATHO".
   There is no good way to avoid this, because this case can't reliably
   be distinguished from the case in which the user does SET HOST
   terminal-server, SET MODEM TYPE name, DIAL. In both cases we have a
   valid modem type selected and we have a network connection. If you
   want to DIAL and then later make a regular network connection, you
   will have to SET MODEM TYPE NONE or SET DIAL HANGUP OFF to avoid this
   phenomenon.
    ________________________________________________________________________

  7. TERMINAL SERVERS

   [ [55]Top ] [ [56]Contents ] [ [57]Next ] [ [58]Previous ]

   Watch out for terminal server's escape character -- usually a control
   character such as Ctrl-Circumflex (Ctrl-^). Don't unprefix it in
   Kermit!

   Ciscos -- must often be told to "terminal download"... Cisco ASM
   models don't have hardware flow control in both directions.

   Many terminal servers only give you a 7-bit connection, so if you
   can't make it 8-bit, tell Kermit to "set parity space".

   The following story, regarding trouble transferring 8-bit files
   through a reverse terminal server, was contributed by an Annex
   terminal server user:

     Using C-Kermit on an HP 9000 712/80 running the HP-UX 10.0
     operating system. The HP was connected to a Xylogics Annex
     MICRO-ELS-UX R7.1 8 port terminal server via ethernet. On the
     second port of the terminal server is an AT&T Paradyne 3810 modem,
     which is connected to a telephone line. There is a program which
     runs on the HP to establish a Telnet connection between a serial
     line on the Annex and a character special file on the HP (/dev
     file). This is an Annex specific program called rtelnet (reverse
     telnet) and is provided with the terminal server software. The
     rtelnet utility runs on top of the pseudo-terminal facility
     provided by UNIX. It creates host-originiated connections to
     devices attached ot Annex serial ports. There are several command
     line arguments to be specified with this program: the IP address of
     the terminal server, the number of the port to attach to, and the
     name of the pseudo-device to create. In addition to these there are
     options to tell rtelnet how to operate on the connect: -b requests
     negotiation for Telnet binary mode, -d turns on socket-leve
     debugging, -f enables "connect on the fly" mode, -r removes the
     device-name if it already exists, etc. The most important of these
     to be specified when using 8 data bits and no parity, as we found
     out, was the -t option. This creates a transparent TCP connection
     to the terminal server. Again, what we assumed to be happening was
     that the rtelnet program encountered a character sequence special
     to itself and then "eating" those kermit packets. I think this is
     all of the information I can give you on the configuration, short
     of the values associated with the port on the terminal server.

   How to DIAL from a TCP/IP reverse terminal server (modem server):

    1. (only if necessary) SET TELNET ECHO REMOTE
    2. SET HOST terminal-server-ip-name-or-address [ port ]
    3. SET MODEM TYPE modem-type
    4. (only if necessary) SET DIAL HANGUP OFF
    5. (for troubleshooting) SET DIAL DISPLAY ON
    6. DIAL phone-number

   The order is important: SET HOST before SET MODEM TYPE. Since this is
   a Telnet connection, serial-port related commands such as SET SPEED,
   SET STOP-BITS, HANGUP (when MODEM HANGUP-METHOD is RS232), etc, have
   no effect. However, in C-Kermit 8.0, if the modem server supports
   [59]RFC-2217 Telnet Com-Port Control protocol, these commands do
   indeed take effect at the server's serial port.
    ________________________________________________________________________

  8. TERMINAL EMULATION

   [ [60]Top ] [ [61]Contents ] [ [62]Next ] [ [63]Previous ]

   Except for the Windows, OS/2, and Macintosh versions, C-Kermit does
   not emulate any kind of terminal. Rather, it acts as a
   "semitransparent pipe", passing the characters you type during a
   CONNECT session to the remote host, and sending the characters
   received from the remote host to your screen. Whatever is controlling
   your keyboard and screen provides the specific terminal emulation: a
   real terminal, a PC running a terminal emulator, etc, or (in the case
   of a self-contained workstation) your console driver, a terminal
   window, xterm, etc.

   Kermit is semitrantsparent rather than fully transparent in the
   following ways:

     * During a TELNET ("set host") session, C-Kermit itself executes the
       TELNET protocol and performs TELNET negotiations. (But it does not
       perform TN3270 protocol or any other type of 3270 terminal
       emulation.)
     * If you have changed your keyboard mapping using SET KEY, C-Kermit
       replaces the characters you type with the characters or strings
       they are mapped to.
     * If you SET your TERMINAL CHARACTER-SET to anything but
       TRANSPARENT, C-Kermit translates your keystrokes (after applying
       any SET KEY definitions) before transmitting them, and translates
       received characters before showing them on your screen.
     * If your remote and/or local TERMINAL CHARACTER-SET is an ISO 646
       7-bit national character set, such as German, French, Italian,
       Swedish, etc, or Short KOI used for Cyrillic, C-Kermit's CONNECT
       command automatically skips over ANSI escape sequences to avoid
       translating their characters. Only ANSI/ISO standard
       (VT100/200/300-like) 7-bit escape sequence formats are supported
       for this purpose, no proprietary schemes like H-P, Televideo,
       Tektronix, etc.
     * If your version of C-Kermit includes SET TERMINAL APC command,
       then C-Kermit's CONNECT command will handle APC escape sequences
       if TERMINAL APC is not set to OFF (which is the default).

   You can make C-Kermit fully transparent by starting it with the -0
   (dash zero) command-line option.

   If you are running C-Kermit under a console driver, or in a terminal
   window, that emulates the VT100, and use C-Kermit to log in to a VMS
   system, the console driver or terminal window (not Kermit) is supposed
   to reply to the "what are you?" query (ESC Z) from the VAX. If it
   doesn't, and you can't make it do so, then you can (a) live with the
   "unknown terminal" problem; (b) tell VMS to SET TERMINAL/DEVICE=VT100;
   (c) program a key using SET KEY to send the appropriate sequence and
   then punch the key at the right time; or (d) use the VMSLOGIN macro
   that is defined in CKERMIT.INI to do this for you automatically.

   SET SESSION-LOG { TEXT, BINARY }, which is effective in UNIX and
   AOS/VS but not other C-Kermit versions, removes CR, DEL, NUL, XON, and