    May 14, 1983


    MODEM7 was done as a "fun" project by:

    Dale J. Travis
    14603 Smith Road
    Lockport, IL  60441
    815-838-2512 evenings
    312-972-6964 days


    The included files are:

    MODEM7.C     C source of the program
    CIO   .MAC   C callable console I/O support routines
    TSXIS .MAC   C callable routine to return true if TSX is running
    TSXRT .MAC   C callable routine to map the I/O page into the user
                  area if TSX is running and is genned for real time
                  support.
    MODEM7.COM   Command file to compile & link MODEM7. There will be
                  a "multiple definition of PUTCHA" from the linker.
                  This is ok. Just be sure you link MODEM7 the way I did.



    The intent of MODEM7 was to have a program  running  under  RT-11  that
    would  be  compatible  with the MODEM7 from the CP/M world. That is the
    only likeness of the two MODEM7's. That is, when you use the  checksum-
    med  modes of the 'o' or 't' commands, the protocol is the same as that
    of the MODEM7 of the CP/M world.

    There is a question to allow the support of the x-on/x-off protocol  of
    the  DEC  world. This is very usefull if you use a computer system run-
    ning MODEM7 as a console of another computer. This will  allow  you  to
    'capture'  all of the conversation on your disk. Just open (o) the file
    on your computer and start using your terminal as if you were  directly
    connected  to the other computer. When you are done, close the file and
    all of your console interaction with the other computer will be in your
    disk file.

    Because the disk I/O is slow (relative to 1 char time at 1200 baud)  x-
    off  will be sent to the modem each time a block is written to the disk
    if you have answered "Are you a DEC computer console" in  the  affirma-
    tive.  There is a 10 char buffer in MODEM7 at this point to collect all
    the chars that the other computer may send after the x-off  is  issued.
    This is done so no chars are lost.

    CTRL-A is used as a lead-in to get to the command prompter.  When  ever
    you want to change something (or do something) type the CTRL-A followed
    by one of the command letters and answer the questions. To get a  list-
    ing of the commands, type CTRL-A and any illegal command (a good one is
    the ? char). This will print the available commands and a brief summary
    of what they do.
                                      