Equisys Technical Notes

Technical guidance, explanations and fixes for our products

PRB: Brooktrout ISDN board ignores calls if channel 0 is set to send only



ID: ZTN1071

This Zetafax technical note applies to:

  • Zetafax 5.5 and later


Incoming calls are rejected on channel 0 when channel 1 is in use, the line will continue to ring until the fax call times out, the sender will not get an engaged tone.


Channel 0 is configured for sending only. If you are using a two-channel BRI board, channel 0 must be configured to receive calls. This is the case for all even numbered channels. (i.e. BTROUT-3 (FAX2) on a quad channel board)

The Brooktrout drivers perform channel mapping, so that the inbound call is mapped to even numbered fax channels, starting at 0.


Set Channel 0 to send and receive or receive only. This is accomplished with the Zetafax configuration program:

Run the Zetafax Configuration program (ZFSETUP.EXE) and select Configure Devices. Highlight the BTROUT-1 entry and click 'Edit'. Ensure 'Connected on channel' is FAX0 and select a Zetafax user or group as the user to receive incoming faxes in the 'Receiving' section of the dialog. Check the 'Use for incoming calls only' if you wish to use the channel exclusively for receiving faxes. Close the program and restart the Zetafax server.


This has been identified by Brooktrout as a limitation with the range of Basic rate interface (BRI) fax boards.

Last updated: 22 June 2000 (GC/GW)


Recent news

As part of our drive towards making the software simpler to use, Zetadocs Expenses now supports single sign-on using Microsoft work or school accounts. This makes it easier for Office 365 ...

This article describes the new features and other improvements in the August 2019 release of the Zetadocs Expenses service. Zetadocs Expenses ...