These programs have not had a lot of use, there may be bugs in them.
I have at least designed filters with all of them that worked.  I have
changed the extension from .BAS to .TXT because the FTP program will not
upload .BAS files.  BASIC will run the .TXT files if you load them with
the extension, ie: LOAD "LOPASS.TXT", or you can change it back to .BAS.

There is a FILTMENU.TXT file which is a BASIC program that provides a
menu for the filter programs.  There is also FILTER.BAT which will start
the filter menu if your BASIC interpreter is named BAS.EXE.  Otherwise,
edit the .BAT file to name your BASIC interpreter.

These programs run in DOS.  They will run in a DOS window, but if your
printer is not DOS compatible, the program may hang.

The tolerance of components is a concern and is more critical as the
number of sections increases.  2% may be OK for a two pole filter, but
a 10 pole will require 1% or better.

The LC design programs require numbers input that you will find in tables
of low pass prototypes.  Some tables that I have used: "Simplified Modern
Filter Design" by Philip R. Geffe, Rider, 1963 and: "Handbook of Filter
Synthesis" by Anatol I. Zverev, John Wiley & sons,1967.

Most of the low pass prototype tables have one ohm input and load 
resistance.  If you want to have unequal terminations, you can do it by
splitting a symmetrical design down the middle and designing each half
for the terminating resistance that you want.  You can then combine the
two halfs and it will work.  Remember that for capacitors in series:
1/C=1/C1 + 1/C2 and for inductors in parallel: 1/L=1/L1 + 1/L2.