Equisys technical notes

Technical guidance, explanations and fixes for our products

PRB: Errors using Zetafax with Brooktrout E1 solutions



ID: ZTN1019

This Zetafax technical note applies to:

  • Zetafax 6 and later


If the Brooktrout E1 (Euro ISDN Primary rate) solution is configured using the textual explanation on the 'Brooktrout Driver Configuration' dialog box the service will be incorrectly set up and you will see a combination of errors from the board including; failures to train; corrupt faxes, fax transmissions not connecting or not hanging up correctly


The 'Brooktrout Driver Configuration' dialog box text states that you should select 'USA' for systems with only ISDN boards. This is correct for all ISDN boards except for PRI boards connecting to E1 circuits, which should be set to the European country you are in. The country selected sets a parameter in the ISDN configuration file (zfax\SERVER\BTROUT\DIGITAL.CFG where 'zfax' is the name of the directory where the Zetafax server files are installed).

This parameter has 2 possible values either A-law or Mu-law and determines what compression algorithm is used for encoding voice traffic over data networks. A-law is for Europe and Mu-law is the value for the USA. When you select 'USA' from the dropdown list it sets DIGITAL.CFG to use Mu-law. The behavior when this parameter is set incorrectly is similar to what you would experience if you had ISDN framing errors. However with the A-law/Mu-Law parameter set incorrectly the ISDN protocol will be established correctly but voice traffic data will be distorted.  As fax is transmitted as voice traffic, having this parameter set incorrectly will disrupt the fax communication.


If you are using PRI boards connecting to E1 circuits:

  1. Stop the Zetafax server.
  2. Use the Start> Programs> Zetafax> Zetafax NT Setup program and select 'Configure Brooktrout boards'.
  3. Select the European country you are in from the 'Country setting for boards' drop down list and click 'Install'. Once the installation is complete you should restart the Zetafax server.


This has been identified by Equisys as a problem with the dialog box text in the software versions given above.

Last updated: 15 February 2000 (GC/DH)

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