                       Commodore 64/128 Kermit v2.2(76)
                          Addendum to v2.2(73) Manual
                                 May 23, 1992

Introduction
------------

This addendum contains information about C-64/128 Kermit v2.2(76), a special 
adaptation of Kermit v2.2 to support the SwiftLink-232 high-speed serial 
interface.  Note that v2.2(76) supports modems interfaced via the SL-232 ONLY 
while v2.2(73) supports modems interfaced via the user port ONLY.  Both
versions are being distributed simultaneously.


Changes from Version 2.2(73)
----------------------------

Kermit v2.2(76) for the SL-232 has very few changes from v2.2(73).  It is not 
considered an upgrade from v2.2(73).  Only changes deemed absolutely necessary 
have been made.  These changes are:

1) Filename changes.  To help differentiate the two versions of Kermit v2.2,
   the SL-232 version has the filename "SLKERMIT" instead of KERMIT.  Similarly,
   the initialization file has the name "SLKERMIT.INI" instead of "KERMIT.INI".
   The autoboot maker program for C-128 users has also been changed from
   "RUN ME NOW!" to "SL RUN ME NOW!".  (If you order a Kermit disk from Kent
   Sullivan, the boot sector has already been installed; therefore, this
   program is not included on the disk.)

   Neither "SLKERMIT.INI" or "SL RUN ME NOW!" are compatible with the
   user-port version of Kermit.

2) SET BAUD command altered.  This command was changed so that it supports
   4800 and 9600 bps, in addition to 300, 1200, and 2400 bps.

3) SET PORT-ADDRESS command added.  This command was added so that Kermit can
   support a SL-232 cartridge at any of the three possible memory addresses,
   $DE00 (the factory default), $DF00, and $D700 (possible on a C-128 only).
   An example of the command is:

      SET PORT-ADDRESS $DF00

   This will change the address that Kermit looks for the SL-232 to $DF00.
   There is also a corresponding SHOW PORT-ADDRESS command.  Note: Besides
   changing the address within Kermit, your SL-232 cartridge must also have
   been modified to "live" at an address other than $DE00.  Consult your SL-232
   documentation for information about this procedure.

4) SET WORKING-DRIVE command added.  This command was added so that you can use
   disk devices other than #8 for loading Kermit, doing file transfers, etc.  We
   felt it was necessary to add this command since many people will want to
   up/download to a fast disk drive (such as a RAM disk--see "Performance
   Considerations / Limitations" below), especially when using higher baud
   rates.  An example of the command is:

      SET WORKING-DRIVE 9

   This will change the disk drive Kermit accesses to device 9.  There is also
   a corresponding SHOW WORKING-DRIVE command.  Note: The WORKING-DRIVE value 
   defaults at boot time to the drive you loaded Kermit from.  It can't be
   saved in the initialization file.

5) Initialization file contents changed.  Besides changing the name of the
   initialization file (described in #1 above), its contents have also changed.
   Because of this, you can't share initialization files between user port and
   SL-232 Kermit.  To make Kermit more robust, we have also removed the need to
   have an initialization file present at boot time.  Kermit v2.2(76) will boot
   properly without a SLKERMIT.INI file, and will use a "reasonable" set of
   defaults.  These default settings may or may not be the settings you prefer.
   (You can always change things then create an initialization file with the
   SAVE command.)

6) SET RS-232 REGISTERS command altered.  This command was changed so that it 
   operates on the SwiftLink-232's control and command registers.  You can use
   this command, for example, to set baud rates higher than 9600.  (These baud
   rates were not included in the SET BAUD command because not all systems can
   keep up at these very high speeds.)  The first byte is the value for the
   control register, while the second byte is the value for the command
   register.  Consult your SwiftLink-232 documentation for a description of the
   appropriate values to use.

7) DISK command altered.  In order to better support third-party disk drives,
   such as CMD's HD-series hard drives, the DISK command has been changed (you
   could call it a "bug fix").  Previously, the DISK command did not allow
   spaces in any of its arguments.  It now does.  You can now type, for example:

      DISK S0:NAME WITH SPACES

   Note: When using a CMD hard drive's "CD <back arrow>" command (native-mode
   subdirectories only), type Shift + "=" for the "<back arrow>".


Performance Considerations / Limitations
----------------------------------------

While the SwiftLink-232 supports baud rates up through 38,400 bps, SL-232
Kermit supports baud rates only up through 9600 bps with the SET BAUD command.
The main reason for this is that Kermit has performance problems keeping up at
these very high speeds.  Kermit was not originally designed to operate at
speeds above 1200 bps (2400 when used on a C-128).  Key sections of the program
were designed to be memory-efficient, not speedy, so operating at high speeds
can cause serious performance problems.  The most visible of these problems is
lost characters on the screen.

As you may know, the user-port version of Kermit does not work at 2400 bps
when using the C-64 80-column screen driver (performance is fine when using
the C-128 80-column screen driver).  SL Kermit improves on this -- it functions
pretty well at 2400 bps when using the C-64 80-column screen driver.  Speeds
above 2400 bps are not recommended when using the C-64 80-column screen driver,
unless you are not too concerned about screen output (i.e., just doing file
transfers).  The SwiftLink-232 cartridge is quite capable of sending and
receiving characters at speeds above 2400 bps; Kermit just doesn't do a good
job of updating the screen when using the C-64 80-column screen driver.

When using the C-128 screen driver, performance is much better.  SL Kermit can
keep up well at speeds up through 9600 bps, especially if flow control is used.

Below are several things you can do to maximize SL Kermit's performance:

1) Turn on flow control.  If you are using Kermit to talk to a remote computer
   which supports flow control, make sure Kermit has flow control turned on.
   You can turn on flow control by typing SET FLOW-CONTROL ON.  Note: This is
   the factory default setting.

2) Reduce the amount of info that is printed to the screen during a file 
   transfer by typing SET DEBUGGING OFF.  Note: The factory default setting is 
   TERSE.

3) Use a fast disk drive.  Stock 1541, 1571, etc., disk drives are very slow
   and cause a bottleneck during file transfers at speeds above 2400 bps.  If
   at all possible, use a fast disk drive for up/downloads.  For best results,
   download to a RAM disk (such as a Commodore 17XX REU running RAMDOS or a
   CMD RAMLink/Drive).

4) Use the Commodore 128 screen driver.  Kermit takes advantage of the 2 Mhz. 
   mode of the C-128 when using the C-128 80-column screen driver.  This extra 
   speed helps Kermit keep up at higher speeds.

5) Use a modem which supports V.32 or V.32bis error control.  Modems with built-
   in error checking can help reduce problems when Kermit has trouble keeping
   up.


C-64/128 Kermit Ordering Information
------------------------------------

C-64/128 Kermit v2.2 now comes in two "flavors": one for the user port only 
(minor version #73) and one for the SL-232 only (minor version #76).  Both of 
these versions and the accompanying documentation are available on major 
computer networks for downloading, as Kermit is freely-distributable.  You can 
also order Kermit (either variety) on a 1541 disk from:

   Kent Sullivan
   16611 NE 26th St.
   Bellevue, WA 98008

Either version on a 1541 disk (with on-disk documentation) is $5.00.
A separate laser-printed manual is $7.50.

Notes: (1) WA residents please add 8.2% sales tax.  (2) U.S. funds only can be 
accepted.  (3) Send check or money order only, please.  Checks will be held 
until they clear, so allow 4-5 weeks for delivery.  (4) Foreign orders should 
add $5.00 per order for airmail shipping.


SwiftLink-232 Ordering Information
----------------------------------

The SwiftLink-232 is a high-speed serial interface that plugs into your C-
64/128's expansion (cartridge) port.  The SL-232 allows much faster serial 
communication because it performs in hardware what the C-64/128 must normally
do in software.  Speeds of up to 38,400 bps are possible with the SL-232 and an 
appropriate high-speed modem or direct network connection.

The SL-232 was originally developed by Dr. Evil Laboratories (also a long-time 
Kermit distributor) but is now sold exclusively by Creative Micro Designs (CMD).  
For information on ordering the SL-232, contact CMD at:

   Creative Micro Designs
   P.O. Box 646
   East Longmeadow, MA 01028
   413-525-0023
