Kermit-80 for the DEC Rainbow-100.

This is a stopgap implementation for the Rainbow.  It is equivalent to
Kermit-80 in every way, with one major exception:

   Rainbow Kermit-80 only works at port speeds of 1800 baud or less!

This is really just a version of "Generic CP/M Kermit-80" that does VT100
screen control.  A specific 8088-based implementation of Rainbow Kermit is in
"alpha test" (see below); meanwhile, this one will have to do.  The speed
restriction is because the serial port is attached to the 8088, and the program
runs on the Z80; the CP/M-80 program must therefore ask the 8088 to do each i/o
operation, which slows things down a lot.

Beware: during terminal connection, the screen may occasionally freeze during
host output.  Just type CTRL-Q to unstick it (some characters may be lost in
the process).  This happens quite rarely at 1800 baud, and practically never
at lower speeds.

By the way, the same program can be run on the VT180, and probably on any other
8080- or Z80-based CP/M micro that does VT100 or ANSI screen control.  It can
also be run on any other CP/M micro, but the screen will be a mess during file
transfer, although the transfer should still work.  During terminal connection,
no interpretation of escape codes is done -- it is left to the
hardware/firmware of the micro.  For CP/M micros that don't do ANSI screen
control, try Generic Kermit itself -- the only difference will be that the
screen will be updated during file transfer as if for a hardcopy -- no screen
control.

Rainbow Kermit should not normally be used in conjunction with a Kermit
Server.  This is because the Rainbow, unlike most other CP/M systems, actually
buffers unrequested input at the serial port for the user program.  Other
systems throw it away, and the Kermit protocol relies on that.  CP/M does not
provide any mechanism to discard the contents of an input buffer.  The Kermit
Server sends out periodic NAK packets when it's between commands, and if these
have piled up in the micro's input buffer, the two sides will get hopelessly
out of synch.  For CP/M systems that don't provide buffering, it will be most
convenient to use Generic Kermit in conjunction with a server, since the
connecting back forth will not be necessary except initially to get the server
started on the remote side.  The 8088-based version of Rainbow Kermit will
rectify this problem.

For Rainbow users with direct-connect modems which require the DTR (Data
Terminal Ready) signal to be "high" in order to communicate with the host,
the program SETDTR.CMD is provided.  Run this program before using Kermit on
the Rainbow.  (Sorry, we don't have sources for it.  It's an 8-bit binary
program that runs on the 8088 side of the Rainbow; the best way to get it is
to copy it from the floppy disk of someone who already has it.)  A
complementary program, CLRDTR.CMD, is also provided to clear DTR, i.e. "hang
up" the connection.

The new 8088-based Rainbow KERMIT is a preliminary version -- that means it's
not yet finished.  It has the following restrictions:

. Runs under CP/M-86/80 version 1 only.  Not version 2 or MS DOS.
. Tested at 4800 baud and keeps up OK.  9600 baud uncertain.
. No wildcard SEND yet.
. Some server commands are supported, but not GET (yet).
. There is code to keep DTR up, but it has not been tested.
. There may be rough edges and bugs here and there.

There's no .HEX file, only a binary .CMD file.  You should be able to
download it using the old KERMIT on the Z80 side.  The program is stored
in the distribution area as RB*.*.  RBKERMIT.CMD is the executable program.
RB*.A86 are the source modules, written in Digital Research CP/M-88 assembler
and assembled on the Rainbow.
