Device/Conrad/RelaisControl 
========================================

This module supports access to a Conrad RelaisCard. Conrad
is a large german electronic stuff dealer. They are selling
a self manufactured card with 8 relais on it. The card
is accessed via serial communication. The card is also
cascadeable up to 255 cards in a ring. 

While the task of accessing such a card is very simple
this distribution contains 3 module files. These are
the abstraction of the whole cascade, the card and the
communcation.

Frame.pm contains the protocol which is used to talk to
the card. RelaisCard.pm is the owner of one single card.
RelaisControl.pm is the container for an arbitrary number
of cards.

For simple tasks you only need the RelaisControl module.
It allows direct access to any port on any card. 

THINGS TO KNOW

- At the moment I don't have a card to test further things. If
  there are important issues to resolve I will get me one :)
- I was never able to test the cascading stuff. The things
  implemented for using multiple cards are just programmed as
  they are documented.
- There are still things hardcoded while they aren't supposed
  to. This includes the location of the lockfile for the serial
  port and the port speed settings. It defaults to 19200,8,n,1
  without any handshake or flowcontrol. I'm not quite sure if
  the card is operating on any other setting.

CAUTION

The card is very dump when it comes to communication. If the
card goes out of acknowledged communication there is no way 
to reinitialize the card and gain control again.
This is very problematic if you have electronics that should
only switched up to a few seconds. If something goes wrong
after you closed the circuit and before opening again your
circuit will stay closed. The only possible action to force
the card to open a circuit is to take away the power supply :(

INSTALLATION

To install this module type the following:

   perl Makefile.PL
   make
   make test
   make install

DEPENDENCIES

This module requires these other modules and libraries:

  Device::SerialPort

CONTACT

If you found a bug or have any question about the module you may
contact me at noha@cpan.org

COPYRIGHT AND LICENCE

Copyright (C) 2002 Norbert Hartl.

This library is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.

