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README.md

Qodem Terminal Emulator

WHAT IS QODEM?

Qodem is a from-scratch clone implementation of the Qmodem communications program made popular in the days when Bulletin Board Systems ruled the night. Qodem emulates the dialing directory and the terminal screen features of Qmodem over both modem and Internet connections.

The Qodem homepage, which includes an extensive archive of Qmodem(tm) releases, a getting started guide, and Qodem binary downloads, is at: http://qodem.sourceforge.net . The Qodem source code is hosted at: https://github.com/klamonte/qodem .

As for Qmodem(tm): Qmodem(tm) was originally written by John Friel III in 1984, eventually being acquired by Mustang Software, Inc. (MSI) in 1991 and distributed until 2000. Qmodem and QmodemPro were acquired by Quintus when it purchased MSI, and their current copyright status is abandonware. Quintus went bankrupt shortly after the MSI acquisition and members of both companies' Boards of Directors were involved in a class-action lawsuit from Quintus shareholders. The lawsuit (C-00-4263 VRW in the Northern District of California, US District Chief Judge Vaughn R Walker presiding) was settled on December 5, 2006 for $10.1 million (with 11% to plaintiffs legal fees). (For those wanting more, Greg Hewgill collected many articles and other media related to Mustang, including its acquisition of Qmodem, in a PDF: http://hewgill.com/mustang/MustangHistory.pdf . I have a copy also at http://qodem.sourceforge.net/qmodem/MustangHistory.pdf .)

OBLIGATORY SCREENSHOTS

Zmodem upload showing single file and batch progress bars

TradeWars 2002

COPYRIGHT STATUS

To the extent possible under law, the author(s) of Qodem have dedicated all copyright and related and neighboring rights to Qodem to the public domain worldwide. This software is distributed without any warranty. The COPYING file describes this intent, and provides a public license fallback for those jurisdictions that do not recognize the public domain.

Qodem incorporates or links to software that is copyrighted and licensed under BSD-like or GPL-like terms. The CREDITS file describes those pieces and their respective licenses. The only Qodem source file with such code is codepage.c, containing a UTF-8 decoding function; all other such code is in the lib directory.

The effective license for the combined Qodem executable differs depending on whether or not it was linked to cryptlib:

  • WITHOUT CRYPTLIB, the combined license terms are effectively the same as the BSD or MIT license: attribution in the source, source is not required to be shared, and there is no warranty.

  • WITH CRYPTLIB, the combined license terms are effectively the same as the GPLv3 license: attribution in the source, source for both cryptlib and Qodem IS required to be shared (even if somehow modified into a SaaS style architecture), and there is no warranty.

Qodem also ships an unmodified copy of the C64 TrueType fonts as developed by Style available at http://style64.org/c64-truetype/ . These fonts are permitted to be redistributed as part of a software package "if said software package is freely provided to end users". Entities wishing to ship packages that are not "freely provided to end users" will need to either remove this font, or negotiate a separate license agreement by contacting Style at http://style64.org/contact-style .

INTENDED AUDIENCE

Qodem is designed to help the following kinds of people:

  • Console users who want a more capable terminal without having to resort to an X-based emulator. Qodem provides a much longer scrollback, screen dump, capture, keyboard macros, very good VT100 emulation, and many more functions.

  • Windows and X11 desktop users who want a full-featured terminal with a keyboard-driven interface. The X11 and Windows versions of Qodem combine the typical conveniences of modern terminals including scrollback, select-and-paste, Unicode support, and a resizable window, with more rare BBS-era features like Zmodem, Kermit, and keyboard macros.

  • Users of telnet/ssh BBSes who would like to use BBS-era features such as: a phone book, Avatar and ANSI emulations (including ANSI music), file transfers, session logging, and many more functions.

  • Those who use serial ports and modems to communicate with embedded devices, headless servers, and remote systems. Qodem supports the serial port, has a modem dialer, and also a special "DEBUG" emulation mode that prints incoming and outgoing bytes in a programmer's hex dump format which can be quite useful in debugging communication with specialized devices.

  • System administrators who need to manage a number of machines. Qodem can keep track of those machines in its phone book, including usernames and passwords, and it can be used to transfer files across a connection that spans multiple firewalls using Zmodem or Kermit.

  • Fans of the original DOS-based Qmodem who knew and loved its unique approach to text-based communication.

BUILDING QODEM

Qodem can be built in several ways:

  • An autoconf build is available: use configure ; make .

  • A very simple barebones build is also provided via make -f build/Makefile.generic.

  • Windows systems can use pre-made project files for Visual C++ 6 (in the vc6qodem, vc6libc, etc. directories) or Borland C++ 5 (files ending in .ide) to create a binary. There is also a command-line make file for Borland C++ 5.

  • Debian packages for qodem and qodem-x11 are available in the build/deb directory.

  • RPM spec files for qodem and qodem-x11 are available in the build/rpm directory.

The INSTALL file has some additional details.

HOW TO USE QODEM

Qodem is driven by the keyboard. It will listen for mouse events, but only to send those to remote systems using the XTERM or X_UTF8 emulations.

Qodem has two main screens: the phone book and TERMINAL mode.

  • The phone book contains a list of sites to access, with each site being customizable for username, password, emulation, toggles, and more. This is the jumping off point for most connections, so by default Qodem starts in phone book mode.

  • In TERMINAL mode keystrokes are passed directly to the "other side".

Qodem is exited by pressing Alt-X while in TERMINAL mode. (If there is no active connection, Ctrl-C will also bring up the exit dialog.) Pressing 'y' or Enter at the exit prompt will exit Qodem.

Nearly all of the time pressing the ESCAPE key or the backtick (`) will exit a dialog and the phone book screen.

Throughout Qodem, the bottom-most line of the screen is used to report status and provide hints about what keystrokes are available. In TERMINAL mode the status line can be turned off with Alt-- (Alt-minus), or toggled between two different forms with Alt-7.

DIFFERENCES BETWEEN THE TEXT (NCURSES), X11, AND WINDOWS VERSIONS

Version 1.0.0 introduces two new builds based on the PDCurses library: an X11 version and a Windows version. These versions in general work the same as the text-based ncurses version, but have a few differences due to the environments. This section describes those differences.


X11 VERSION

The X11 version can be built by passing --enable-x11 to configure. Due to how the curses libraries are linked, a single Qodem binary cannot currently support both text ncurses and X11 PDCurses interfaces, therefore the X11 binary is 'qodem-x11', and its man page is accessed by 'man qodem-x11'.

The Fedora and Debian package is 'qodem-x11'. It can be installed entirely independently of the normal 'qodem' package.

When spawning other processes such as editors (Alt-L, Alt-N, Alt-V, and editing files in the phone book), the mail reader (Alt-M), or shelling to the OS (Alt-R), Qodem spawns them inside a separate X11-based terminal window, and displays the message "Waiting On X11 Terminal To Exit..." until the other terminal closes. The default terminal program is 'x-terminal-emulator'; this can be changed in qodemrc.

Mouse motion events do not work due to limitation in the PDCurses mouse API. Mouse clicks however do work.

WINDOWS VERSION

The Windows version can be built using either Borland C++ 5 or later, or Microsoft Visual C++ 6 or later.

When spawning other processes such as editors (Alt-L, Alt-N, Alt-V, and editing files in the phone book), the mail reader (Alt-M), or shelling to the OS (Alt-R), Qodem waits for the program to exit.

Quicklearn scripts are written in Perl. Strawberry Perl for Windows is available at http://strawberryperl.com .

The Windows build uses Beep() rather than SDL for sounds. This might not work on Windows Vista and 64-bit XP systems.

SSH connections (client or host) using cryptlib do not work when compiled with the Borland compiler.

Mouse motion events do not work due to limitation in the PDCurses mouse API. Mouse clicks however do work.

KNOWN ISSUES / DECISIONS

In the development of Qodem some arbitrary design decisions had to be made when either the obviously expected behavior did not happen or when a specification was ambiguous. This section describes such issues.


The ncurses version of Qodem requires a Unicode-capable Linux console or X emulator to look right. For the Linux console, the default settings for most Linux distributions should work well. Under X11, xterm, rxvt-unicode, and Konsole work well.

Most BBS programs assume a display with 80x24 dimensions. Qodem by default sets the right margin to column 80 for ANSI, Avatar, and TTY emulations. Changing "80_columns = true" to "80_columns = false" in qodemrc will cause Qodem to use the real right margin.

The backspace key is always mapped to DEL (0x7F) in VT220 emulation to match the keyboard of a real VT220. You can send a true backspace (0x08, ^H) by pressing Alt-\ 0 0 8 to use the Alt Code Key feature to send backspace.

Function keys beyond F4 in VT100/VT102 emulation may not work as expected. Qodem uses a common convention that F5 is "{ESC} O t", F6 is "{ESC} O u", etc. Some programs understand this convention. Those that don't will usually understand "{ESC} {number}", where {number} is a number from 5 to 0, to mean F5 through F10. You can get this effect in Qodem by typing ESC {number}, or by switching to Doorway Mode and typing Alt-{number} (or Meta-{number}).

In VT100, VT102, and LINUX emulations, some programs (like minicom and Midnight Commander) send the DECCOLM sequence ({ESC} [ ? 3 l ) when exiting, putting the emulation into 80-column mode. Resetting the emulation via Alt-G {pick emulation} {enter 'y'} will restore the default right margin.

ASCII uploads may hang if the remote end can't keep up. For instance, using 'vi' to create a large file and ASCII uploading the contents may hang after a few kilobytes. 'cat > filename' usually works fine.

ASCII downloads will process the TAB character (0x09) as a control character, causing it to expand to the appropriate number of spaces.

Malformed escape sequences might "freeze" LINUX or VTxxx emulation. (For example, receiving a 0x90 character causes VT102 to look for a DCS sequence. If the DCS sequence is not properly terminated the emulation won't recover.) Resetting the current emulation will restore the console function.

KEY_SUSPEND is usually mapped to Ctrl-Z and used to suspend the local program ('qodem'). If Qodem sees KEY_SUSPEND it will assume the user typed Ctrl-Z and meant to pass that to the remote side.

On Ymodem downloads, if the file exists it will be appended to.

Xmodem and Ymodem downloads from hosts that use the rzsz package might need to have stderr redirected to work correctly, for example 'sb filename 2>/dev/null' .

Kermit receive mode by default handles file collisions by saving to a new file (SET FILE COLLISION RENAME / WARN file access Attribute). It supports the APPEND file access Attribute but disregards the SUPERSEDE file access Attribute.

When sending files via Zmodem to HyperTerminal, if the HyperTerminal user clicks "Skip file" then the transfer will stall. This appears to be due to two separate bugs in HyperTerminal: 1) When the user clicks "Skip File", HyperTerminal sends a ZRPOS with position==file size, Qodem responds by terminating the data subpacket with ZCRCW, which HyperTerminal responds to with ZACK, however the ZACK contains an invalid file position. 2) Qodem ignores bug #1 and sends ZEOF, to which HyperTerminal is supposed to respond with ZRINIT, however HyperTerminal hangs presumably because it is expecting the ZEOF to contain a particular file position, however the position it desires is neither the true file size nor the value it returned in the ZACK.

Mark and space serial port parity are only supported for 7 data bits. This is due to a limitation of the POSIX termios API. Workarounds for the other bit settings (5, 6, 8) are possible if there is user demand.

GNU Emacs may look wrong in ANSI emulation when Line Wrap is disabled.

Internal telnet and rlogin connections usually do not successfully pass the LANG environment variable to the remote host. (Qodem sends the LANG variable and value, but most remote daemons do not listen for it.)

The SSH server key fingerprint displayed in the Alt-I info screen is unique, but does not match the key fingerprints reported by ssh-keygen or the OpenSSH client.

The ssh library used by the host mode SSH server (cryptlib) has a known issue accepting connections from ssh clients that request DH keys larger than 4096 bits. See http://article.gmane.org/gmane.comp.encryption.cryptlib/2793 for some discussion regarding this. ssh clients to a Qodem host can pass the '-m hmac-md5' command line argument to work around this.

The host mode SSH server does not care what username or password are passed through the ssh client. After the ssh connection is established, the login sequence is identical to socket and telnet connections.

Qodem manages its own known_hosts file for SSH connections. This file is stored in the ~/.qodem directory (or Documents\qodem\prefs on Windows).

When using 'raw' mode for the capture file, host mode includes its outgoing bytes in the capture file.

SCRIPT SUPPORT

Qodem has an entirely different method for supporting scripts than Qmodem. This section describes the Qodem scripting support.


Qodem does not have its own scripting language. Instead, any program that reads and writes to the standard input and output can be run as a Qodem script:

  • Characters sent from the remote connection are visible to the script in its standard input.

  • Characters the script emits to its standard output are passed on the remote connection.

  • Messages to the standard error are reported to the user and also recorded in the session log.

Since scripts are communicating with the remote system and not Qodem itself, they are unable to script Qodem's behavior, e.g. change the terminal emulation, hangup and dial another phone book entry, download a file, etc. However, they can be written in any language, and they can be tested outside Qodem.

Scripts replace the user, and as such have similar constraints:

  • Script standard input, output, and error must all be in UTF-8 encoding.

  • Scripts should send carriage return (0x0D, or \r) instead of new line (0x0A, or \n) to the remote side - the same as if a user pressed the Enter key. They should expect to see either bare carriage return (0x0D, or \r) or carriage return followed by newline (0x0D 0x0A, or \r\n) from the remote side.

  • Input and output translate byte translation (the Alt-A Translate Tables) are honored for scripts.

  • While a script is running:

    • Zmodem and Kermit autostart are disabled.
    • Keyboard function key macros are disabled.
    • Qodem functions accessed through the Alt-character combinations and PgUp/PgDn are unavailable.
    • Pressing Alt-P will pause the script.
  • While a script is paused:

    • The script will receive nothing on its standard input.
    • Anything in the script's standard output will be held until the script is resumed.
    • The script process will not be signaled; it may continue running in its own process.
    • The only Alt-character function recognized is Alt-P to resume the script. All other Alt- keys will be ignored.
    • Keys pressed will be sent directly to the remote system.
    • Keyboard function key macros will work.

Scripts are launched in two ways:

  • In TERMINAL mode, press Alt-F and enter the script filename. The script will start immediately.

  • In the phone book, add a script filename to a phone book entry. The script will start once that entry is connected.

Script command-line arguments can be passed directly in both the Alt-F script dialog and the phone book linked script field. For example, pressing Alt-F and entering "my_script.pl arg1" will launch my_script.pl with its first command-line argument ($ARGV[0] in Perl) set to "arg1".

TERMINAL EMULATION LIMITATIONS

This section describes known missing features in a Qodem emulation.


The following features are not supported for VT10x: smooth scrolling, printing, keyboard locking, and tests.

132-column mode in VT100 is supported only within consoles/emulators that have 132 (or more) columns available. For instance, 132-column VT100 output on a 128-column Linux console screen will result in incorrect behavior.

VT52, VT10x, VT220, LINUX, and XTERM numeric/application keypad modes do not work well in the text version. This is due to Qodem's host console translating the numeric keypad keys on its own before sending the keystroke to the (n)curses library. For example, the Linux console will transmit the code corresponding to KEY_END when the number pad "1 key" is pressed if NUMLOCK is off; if NUMLOCK is on the console will transmit a "1" when the "1 key" is pressed. Qodem thus never actually sees the curses KEY_C1 code that would instruct Qodem to transmit the appropriate string to the host system. The only key that appears to work right on most consoles is the number pad "5 key" (KEY_B2). The X11 version of Qodem supports the number pad correctly.

VT52 HOLD SCREEN mode is not supported in any emulation (VT52, VT10x, LINUX, XTERM).

In VT52 graphics mode, the 3/, 5/, and 7/ characters (fraction numerators) are not rendered correctly.

In addition to the VT100/VT102 limitations, the following features are not supported for VT220: user-defined keys (DECUDK), downloadable fonts (DECDLD), VT100/ANSI compatibility mode (DECSCL). (Also, because the VT220 emulation does not support DEC VT100/ANSI mode, it will fail the last part of the vttest "Test of VT52 mode".) The unsupported commands are parsed to keep a clean display, but not used otherwise.

VT220 discards all data meant for the 'printer' (CSI Pc ? i).

The ANSI.SYS screen mode switch sequence (ESC [ = Pn {h | l}) only supports enable/disable line wrap (Pn = 7); the various screen mode settings (e.g 40x25 mono, 640x480 16-color, etc.) are not supported.

XTERM (and X_UTF8) recognizes only a few more features than LINUX and VT220. It does not support most of the advanced features unique to XTerm such as Tektronix 4014 mode, alternate screen buffer, and many more. It is intended to support XTerm applications that only use the sequences in the 'xterm' terminfo entry.

PETSCII colors do not exactly match true Commodore colors. Also, uppercase/lowercase switches new incoming characters but does not change the existing characters on the screen.

DEVIATIONS FROM QMODEM

Qodem strives to be as faithful as possible to Qmodem, however sometimes it must deviate due to modern system constraints or in order to go beyond Qmodem with entirely new features. This section describes those changes.


The default emulation for raw serial and command line connections is VT102 rather than ANSI.

Qodem will listen for mouse events and send them to the remote side using the same wire protocol as xterm's X10, UTF8, or SGR encoding. It supports the X10-, normal-, button-, and any-event-tracking modes. This is only available for XTERM and X_UTF8 emulations. Note that ncurses will not report any-event mouse events to Qodem unles TERM is "xterm-1003"; similarly button-event tracking requires TERM to be "xterm-1002".

The IBM PC ALT and CTRL + {function key} combinations do not work through the curses terminal library. CTRL-Home, CTRL-End, CTRL-PgUp, CTRL-PgDn, Shift-Tab, and ALT-Up have been given new key combinations.

The F2, F4 and F10 function keys are often co-opted by modern desktop environments and unavailable for Qodem. F2 and F10 are still supported, but also have additional keys depending on function. Most of the time space bar can be used for F2 and the Enter key for F10. The status bar will show the alternate keystrokes. F4 is currently only used to clear the Batch Entry Window and show/hide dotfiles in the View Directory window, no alternative keystroke is provided.

The ESCAPE key can have a long delay (up to 1 second) under some installations of curses. It is still supported, but the backtick (`) can also be used for faster response time. See ESCDELAY in the curses documentation.

The program settings are stored in a text file usually called $HOME/.qodem/qodemrc. They are hand-edited by the user rather than another executable ala QINSTALL.EXE. The Alt-N Configuration command loads the file into an editor for convenience.

The batch entry window is a simple form permitting up to twenty entries, each with a long filename. Next to each entry is the file size. The Qmodem screen was limited to three directories each containing up to twenty 8.3 DOS filenames, and did not report file sizes. The F3 "Last Found" function is not supported since many systems use long filenames.

The upload window for Ymodem, Zmodem, and Kermit contains a second progress indicator for the batch percentage complete.

Alt-X Exit has only two options yes and no. Qmodem offers a third (exit with DTR up) that cannot be implemented using Linux-ish termios.

External protocols are not yet supported.

Some functions are different in TERMINAL mode:

    Key        Qodem function         Qmodem function
    ----------------------------------------------------------
    Alt-K      Send BREAK             Change COM Port
    Alt-L      Log View               Change drive
    Alt-O      Modem Config           Change directory
    Alt-P      Capture File           COM Parameters
    Alt-Y      COM Parameters         Auto Answer
    Alt-Z      Terminal Mode Menu     -
    Alt-2      Backspace/Del Mode     80x25 (EGA/VGA)
    Alt-3      Line Wrap              Debug Status Info
    Alt-4      Display NULL           80x43/50 (EGA/VGA)
    Alt-9      Serial Port            Printer Echo
    Alt-+      CR/CRLF Mode           -
    Alt-,      ANSI Music             -
    Alt-\      Alt Code Key           -
    Alt-:      Colors                 -
    Alt-/      Scroll Back            -
    Alt-;      Codepage               -
    Home       -                      Terminal Mode Menu
    Alt-Up     -                      Scroll Back
    Ctrl-End   -                      Send BREAK
    Ctrl-Home  -                      Capture File
    Shift-Tab  -                      CR/CRLF Mode

The phone book stores an arbitrary number of entries, not the hard-coded 200 of Qmodem.

The directory view popup window allows up to 20 characters for filename, and the Unix file permissions are displayed in the rightmost column.

The directory browse window behaves differently. Scrolling occurs a full page at a time and the first selected entry is the first entry rather than the first file. Also, F4 can be used to toggle between showing and hiding "hidden files" (dotfiles) - by default dotfiles are hidden.

The phone book displays the fully-qualified filename rather than the base filename.

VT100 escape sequences may change terminal settings, such as line wrap, local echo, and duplex. The original settings are not restored after leaving VT100 emulation.

DEBUG_ASCII and DEBUG_HEX emulations are not supported. Qodem instead offers a DEBUG emulation that resembles the output of a programmer's hex editor: a byte offset, hexadecimal codes, and a region of printable characters.

TTY emulation is actually a real emulation. The following control characters are recognized: ENQ, BEL, BS, HT, LF, VT, FF, CR. Also, underlines that would overwrite characters in a typical character cell display will actually underline the characters. For example, A^H_ ('A' backspace underline) will draw an underlined 'A' on a console that can render underlined characters.

ANSI emulation supports more codes than ANSI.SYS. Specifically, it responds to DSR 6 (Cursor Position) which many BBSes used to "autodetect" ANSI, and it also supports the following ANSI X3.64 functions: ICH, DCH, IL, DL, VPA, CHA, CHT, and REP. It detects and discards the RIPScript auto-detection code (CSI !) to maintain a cleaner display.

The "Tag Multiple" command in the phone book does not support the "P{prefix}{number}{suffix}" form of tagging. Number prefixes and suffixes in general are not supported. Also, text searching in both "Tag Multiple" and "Find Text/Find Again" is case-insensitive.

The "Set Emulation" function has the ability to reset the current emulation. For example, if Qodem is in ANSI emulation, and you try to change to ANSI emulation, a prompt will appear asking if you want to reset the current emulation. If you respond with 'Y' or 'y', the emulation will be reset, otherwise nothing will change. This is particularly useful to recover from a flash.c-style of attack.

"WideView" mode in the function key editor is not supported.

"Status Line Info" changes the status line to show the online/offline state, the name of the remote system (in the phone book), and the current time. Qmodem showed the name of the system, the phone number, and the connect time.

The scripting language is entirely different. Qodem has no plans to support Qmodem or QmodemPro scripts.

Qmodem had several options to control Zmodem behavior: overwrite files, crash recovery, etc. Qodem does not expose these to the user; Qodem's Zmodem implementation will always use crash recovery or rename files to prevent overwrite when appropriate.

Qodem always prompts for a filename for capture, screen dump, saved scrollback, and session log. (Qmodem only prompts if the files do not already exist.) Exception: if session log is specified on a phone book entry toggle, Qodem will not prompt for the filename but use the default session log filename specified in qodemrc.

Qodem supports two kinds of DOORWAY mode: "Doorway FULL" and "Doorway MIXED". "Doorway FULL" matches the behavior of Qmodem's DOORWAY mode. "Doorway MIXED" behaves like DOORWAY EXCEPT for a list of commands to honor. These commands are stored in the qodemrc 'doorway_mixed_mode_commands' option. "Doorway MIXED" allows one to use PgUp/PgDn and Alt-X (M-X) in Emacs yet still have ALT-PgUp/ALT-PgDn, scrollback, capture, etc.

Qodem includes a Alt Code Key function (Alt-\) for entering a raw decimal byte value (0-255) or a 16-bit Unicode value (0-FFFF).

Capture, screen dump, and saving scrollback can be saved in several formats (configured in qodemrc). "normal" behaves like Qmodem: colors and emulation commands are stripped out, leaving a UTF-8 encoded black-and-white text file. "html" saves in an HTML format that includes colors. For capture only, "raw" saves the raw incoming byte stream before any UTF-8 decoding or emulation processing. For all save formats, "ask" will bring up a dialog to select the save format every time the save is requested. For phone book entries that specify a capture file, if the capture type is "ask" it will be saved in "normal" format.

Host mode behaves differently. It uses simple ASCII menus rather than CP437 menus, provides no "Optional Activities", and has fewer features than Qmodem's Host Mode implementation. However, in addition to listening on the modem, it can also listen on TCP ports for raw socket, telnet, and ssh connections; optionally the TCP port can be exposed via UPnP to the general Internet.

TRANSLATE TABLES

Qodem has a slightly different method for translating bytes and Unicode code points than Qmodem's Alt-A Translate Table function. This section describes the Qodem Translate Tables.


The Alt-A Translate Table function has been renamed to Translate Tables (plural), and encompasses both 8-bit and Unicode conversions. The data flow is as follows:

  • Bytes received from the wire are converted according to the 8-bit INPUT table before any other processing. Similarly, bytes are converted through the 8-bit OUTPUT table before being written to the wire.

  • Code points written to the screen are converted according to the Unicode INPUT table. Code points read from the keyboard are converted through the Unicode OUTPUT table before being converted to UTF-8.

  • When using 8-bit codepages, Qodem attempts to convert code points read from the keyboard back to the correct 8-bit codepage value based on several strategies. If no values can be found, '?' is sent instead.

  • Capture, scrollback, screen dump, and keyboard macro files are stored in untranslated formats where possible. 'raw' capture records bytes before the 8-bit tables are applied; 'normal' capture and other files record code points after 8-bit tables are applied but before Unicode tables are applied.

  • 8-bit and Unicode tables can be specified for each phonebook entry.

  • An EBCDIC-to-CP437 table is provided, but is largely untested.

DOCUMENTATION

Qodem has three sources of documentation:

  • This README.

  • Online help, accessed in most screens by pressing F1.

  • The qodem and qodem-x11 man pages.

CONTRIBUTING

Qodem is dedicated to the public domain. Anyone is free to see and modify the source code and release new versions under whatever license terms they wish.

The official repository is hosted on github at https://github.com/klamonte/qodem . Pull requests are very much welcomed.

ACKNOWLEDGMENTS

We'd like to thank the following individuals:

  • John Friel III for writing Qmodem which was the inspiration for this project.

  • Paul Williams, for his excellent work documenting the DEC VT terminals at http://www.vt100.net/emu/dec_ansi_parser .

  • Thomas E. Dickey, for his work on the xterm emulator and the ncurses library. Both Mr. Williams and Mr. Dickey have answered numerous questions over the years in comp.terminals that were archived and greatly aided the development of Qodem's emulation layer.

  • Bjorn Larsson, William McBrine, and the many developers involved in PDCurses who dedicated their work to the public domain.

  • Miquel van Smoorenburg and the many developers involved in minicom who licensed their work under the GNU General Public License.

  • Thomas BERNARD and the developers involved in miniupnpc who licensed their work under a BSD-like license.

  • Jeff Gustafson for creating the Fedora RPM build script.

  • Martin Godisch for help in packaging for the deb build.

  • Jason Scott for creating "BBS: The Documentary".

  • Peter Gutmann for developing cryptlib and licensing it under an open source compatible license.

  • Nathanael Culver for obtaining Qmodem 2.3, 4.2f, and QmodemPro 1.50.

  • Tim Hentenaar for the original version of the ATASCII code.