HEXLINK       Version 1.0
        by Lester Veenstra  K1YCM/3
        Frederick MD
           Voice Day: (301)-428-4390
           Voice Eve: (301)-662-6702
           BBS:       (301)-371-6271 (300/1200)

    This program is intended to solve the problem of how do you get the
first copy of a modem program into a system that does not have a disk
format compatible with the available source.  HEXLINK allows the
transfer of .COM, or for that matter, any file to a minimum CP/M system
containing only the utilities as supplied by Digital Research, PIP and
LOAD.  HEXLINK is only needed in the source system, not the receiving
system.  No code has to be hand entered on the receiving system.

    Typical Use:   The source system that has MODEM7xx will assemble and
overlay a version suitable for the target system.  HEXLINK will then be
used to send the configured MDM7xx.COM to the new system.  The new
system will load the MDM7xx.HEX file that has been created and use it
for further file transfers.

    HEXLINK is a simple file transfer program that uses only ASCII
characters and that does not require the use of a special program in the
receiving machine.  The unique feature of HEXLINK is that it supports
long files that would normally over run a capture buffer.  It is
intended that the receiving machine uses PIP in the block mode to input
via the RDR: logical port.  HEXLINK periodically stops and causes the
receiving machine to empty its buffer to the specified disk file.  The
link is one-way.  That is, HEXLINK does not test the condition of the
receiving system.  Instead it waits a safe period to allow all disk
activity to finish at the receiving machine before sending more
characters.  The file is sent in the Intel hex format.  Thus each line
contains a checksum.  The receiving system must "load" the received .HEX
file to reconvert it back to a .COM file.  Any link errors will be
detected at this time.

    To use HEXLINK, the receiving system must first be set-up with a PIP
command such as:

        PIP B:FILENAME.HEX=RDR:[EB]

    The sending machine can then start HEXLINK and follow the prompts
issued by the program.  The name of the file to be sent should be
unique.

    HEXLINK is useful as a first step in getting a more useful file
transfer program such as MODEM7xx.COM into a new machine when the disk
format is not available.