It was reported to me that on two occasions the communication between the computers was brutally broken. I got two log-files and one of the suspect files.
  The log-files showed that the last transmitted packet included similar strings of characters.
  We were able to transfer the suspect file to a different computer environment, where we could make some tests.
  In this new environment the connection also broke as I anticipated.
  After some thinking we provided a solution to sidestep this problem. But that´s another story...

  I´ve found one report on Internet indicating that the special character sequence might do harm even by reading about this problem. That´s the reason I haven´t not included it in this text.

  Before proceeding I´ll warn you, this might knock you off-line. I´m not doing this on purpose to harass you.

  You are invited to investigate the defect and your modem.

  Of course, you are now curious about what character sequence are we talking about. Here it is.

  Now to make it more interesting and educational I´d like to propose the following:

1. Look in this list E-Tech CYBER-Bullett E56K and ready for the next item and see if your modem is in there. If it is, we know it´s faulty and there´s nothing we can do to cure it.
2. If it´s not in the list, would you, please, send an email to yourself, with the previously shown command string in the body. If you´re not knocked off-line, fine, then you know your modem is among the unaffected ones.
3. If you got knocked off-line, would you, please, send an email to me, stating the complete name of your modem. I intend to update the list as I get input. It´d make it possible for another visitor to identify which modems to avoid when it comes to a purchase decision. Please, don´t send reports on a no-name modem. It´ll be pretty hard to identify.

  Here´s a little analyzis of the design shortcoming in some modems.