Kermit-80 for the DEC Rainbow-100.

This is a stopgap implementation for the Rainbow (see the end of this file for
information about a native CP/M-86 version).  The major problem with using
KERMIT-80 on the Rainbow is that:

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

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.

Rainbow Kermit-80 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.

KERMIT-80 runs only under CP/M-80/86 version 1.  It does NOT run under 
version 2.  The symptoms reported generally involve file transfer hanging
after about 10 packets.


  KERMIT-86 for the Rainbow:

There is now a preliminary version of a native CP/M-86 KERMIT for the Rainbow.
It is in <KERMIT>RB*.*.  The functionality is primitive compared to the CP/M-80
version (which now has built-in ERA, DIR, and SET DEFAULT disk commands), but
it can do terminal emulation and file transfer at speeds up to 9600 baud
(perhaps 19,200).  See <KERMIT>RBKERMIT.HLP for details.
