TECHNICAL BULLETIN #72 - Rev 1.10 (5/13/96)

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TITLE   : Error Correction Mode (ECM)
PRODUCT : PROCOMM PLUS for Windows, All versions
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To insure the integrity of your faxes, PROCOMM PLUS for Windows uses Error
Correction Mode (ECM).  This document describes ECM and provides some tips on
configuring PROCOMM PLUS' ECM abilities.

WHAT IS ECM?
Error correction mode (ECM) is a feature built into Class 1 faxes.  ECM
automatically detects and corrects errors in the fax transmission process that
are sometimes caused by telephone line noise.  ECM is particularly important
when using the Binary File Transfer (BFT) option since it prevents binary
files from being corrupted due to noise on the phone line.

Normally, ECM operation is transparent to the user.  After a Class 1 fax
connection has been negotiated, PROCOMM PLUS automatically negotiates for the
use of ECM if the fax device on the other end of the phone line supports it.

However, you may occasionally encounter a combination of hardware or software
on the other end of the phone line that does not properly implement the use of
ECM and the fax transmission will fail.  You may then find it necessary to
turn off ECM in order to send or receive faxes reliably with the other system.

TURNING OFF ECM IN PROCOMM PLUS for Windows 3.x
The following procedure allows you to configure PROCOMM PLUS' ECM feature.

1. Click "Setup" then "Fax" then "Fax connection" then "Advanced."

2. Set "Fax ECM during send" to NONE.
3. Set "Fax ECM during recieve" to NONE.
4. Click "Ok"

TURNING OFF ECM IN PROCOMM PLUS for Windows 2.x
The following procedure allows you to configure PROCOMM PLUS' ECM feature.

1. Close PROCOMM PLUS for Windows if it is running.

2. Use the Windows Notepad utility to open the PW2.INI file located in the main
   Windows directory (usually called C:\WINDOWS).

3. Scroll through the [Options] section of the PW2.INI file and add FECM="xy"
   immediately below the [Options] line

   Valid values for x and y are:
       0 to turn Error Correction Mode OFF
       1 to turn Error Correction Mode ON

   The x value is for sending faxes and the y value is for receiving faxes.
   Use FECM=01 initially.  This combination will disable ECM on faxes you
   send, but not on faxes you receive.  If you have trouble both sending and
   receiving faxes, use FECM=00.  
   
   Note:  If you do not find the [Options] section in the PW2.INI file, just
   add this section to the end of the file.

4. Once you have made your change to the PW2.INI file, choose Exit from the
   File menu of Notepad.  Click on the Yes button when you are prompted to
   save changes to PW2.INI.

5. Run PROCOMM PLUS for Windows and try another fax transmission with
   the problematic system.

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