ERMON README File

ERMON - ERMES radio path traffic monitor


0. Disclaimer
-------------
    ERMON is a hobby project built for educational purposes. It is not a commercial software.
You may freely use it for non-commercial purposes. It is not allowed to sell this program
or place it to a pay-per-access site or media. You are free to distribute this software
as long as you don't charge for it.
    It is also not allowed to disassemble, debug or recompile this software.
    Please bear in mind that in some countires it might be illegal to decode ERMES
transmissions. Author of this program cannot be held responsible for abusing of this
software. It is your responsibility to check status of your local law regarding ERMES
transmission monitoring, before you use ERMON.
    If you do not agree with the above statements, just delete ERMON and related files and
do not use it anymore.


1. Introduction
---------------
    ERMES is one of the many paging standards used throughout the world. In fact ERMES was
chosen as an European paging standard. It is disputable whether or not it will really
become a standard but nevertheless it might be useful to get a more deeper view into
ERMES functioning.
    ERMON is a software which was designed not only to decode and display ERMES messages, but
it is also capable of displaying of whole ERMES data stream, including control commands
and so on. ERMON also can record ERMES transmission into a binary file, which could be
decoded later. It is possible to set various filtering options depending on the pager
address. All traffic can be logged into a text file. Also every subscriber can now be
logged into separate file, so it is easier to debug ERMES datastream.


2. What you need to decode ERMES
--------------------------------

a) Receiver

- must be able to tune from 169.4125 MHz to 169.8125 MHz - NFM.
- audio discriminator output is neccessary, try using your favorite search engine
  for finding some info on modifying your radio.


b) 4FSK interface

- because ERMES uses 4FSK (or 4PAM/FM) modulation, you need some 4FSK demodulator.
  Unless you already have one, it is possible to build one quite easy, 
  you can find some good designs here: 
    Design by PA3EIK (http://www.qsl.net/pa3eik/4lev_fsk.htm)
    Another design on DSL's pages (http://www.geocities.com/CapeCanaveral/Hangar/8539/DIAGRAM.HTM)

  I personally prefer the first one because of integrated negative voltage supply but it
  seems to be a little less stable than a standard dual voltage setup.


c) PC to run ERMON

- I suppose you can run ERMON successfully on some slower 486 too, but it depends and you have 
  to try yourself. ERMON is a DOS native program. It is also possible to run it under Win95, but 
  unless you have really fast PC, you may lose some data. 


d) ERMON itself

- Since you are reading this, it is very possible you already have one :-)


3. ERMON history
----------------
    ERMON is basically based on a source code called ERMES3.CPP written by 'shrd_lu@hotmail.com'.
I have used interrupt & error correcting routines from this code. The very first versions
of ERMON were designed for a soundcard use but later I decided to use 4FSK instead. However
it is still possible to add a soundcard support if I decide to.

0.4  : 02/07/99
       initial release

0.41 : 03/20/99
       +bug removed: cannot use another COM than COM1
       +option added: V to disable 50/43 lines text mode
                      I for reversing input polarity
       +minor improvements

0.45 : 03/23/99
       +added support for long messages

0.50 : 03/30/99
       non-public beta tester release due to massive
       code changes

0.51 : 04/02/99
       +new decoding routine- faster and more robust
       +new PCM file format- 8 times shorter
       +real time decoding
       +various code improvements

0.52 : 05/12/99
       +numerous minor bugs removed
       +continuous log support added

0.53 : 05/31/99 (non-public)
       +added filtering ('A' & 'F' options)
       +finally some README.TXT file :-), but not completed yet :-(
       +various code improvements
       +reversed effect of 'P' option

0.60 : 06/24/99
       +basically a public 0.53
       +just a few typos corrected

0.70 : 09/23/99
       +added extended logging mode L2, now every subscriber can have his
          own log file on your harddrive
       -tired of waiting for some feedback



4. ERMON options
----------------

    You can get some help by running "ERMON H" or "ERMON ?". You will get a list
of all available options which will be discussed in detail here:


V: disables using of so called "EGA lines" text mode. You may also try to use
   this switch if you have problems with default 43/50 lines text mode.

H or ?: displays basic help screen.

Rname: record a binary file from 4FSK input.

I: reverses polarity of data read from 4FSK.

Cn: COM port number. COM1 is default.

Sname: sets a data source for ERMON. 
       S4 sets for using 4FSK interface.
       Sfile is a file replay.

Dn: debug mode. 
    D1 displays some more info.
    D2 displays all available additional data.

P: enables a pause mode for file replay. 
   You have to press a key after any (even empty) data batch.

Ln: log mode. 
    L1 logs all displayed data into one log file. 
    L2 logs every allowed address into separate file, can be used
       only together with F2 filtering, otherwise one can get a directory
       full of thousands of files.
       
A: process alphanumeric messages only.

F: filtering. 
   F1 uses file REJECT.ERM for a list of banned addresses which
     should be rejected from processing.
   F2 uses file ACCEPT.ERM for a list of allowed addresses which only
     will be allowed for processing.



    Format of *.ERM files is simple, every address has to begin
on a new line, you can also put in your own comments like this:

-----REJECT.ERM sample----------

# This is a sample REJECT.ERM file 
# blah

0400140     # Some strange address
0400011     # Don't want to see this
0411444     # And this also

-----end of sample--------------

Currently you may put up to 2000 addresses into each file.



5. ERMON troubleshooting
------------------------

    ERMON is by default set up for using 4FSK interface on COM1. So if
you run ERMON without any options, ERMON will happily run expecting
4FSK input on COM1. If there is some valid ERMES data, ERMON will
display time&date together with some other numbers on the lower part
of screen and it will wait for some messages.
    If nothing happens you may have some hardware problem - receiver or
interface may be malfunctioning. Press Q and try to detect a problem.
    It is also possible that you have inverted audio output from the 
receiver. Try to use "I" switch and see if it makes any difference.

...To be continued



6. To-do list
-------------

a) National character set support
   Maybe in form of a translation table. Not included due to a lack of feedback
from users.

b) 8-bit data transmission processing
   ERMON already includes code to detect 8-bit data transmission, but it seems
not to be used yet, so I couldn't make necessary tests. Maybe later.

c) Roaming subscribers
   Same as 8-bit data - detected, but not processed.

d) Soundcard support
   Since nobody is interested I will not bother to code it - I have another work
to make my living :-)




7. Author
---------

    You are welcome to send some feedback or your opinions to my e-mail.
Since it sometimes changes, it is best to use e-mail address found on help
screen of the latest ERMON version.
