Equisys technical notes

Technical guidance, explanations and fixes for our products

PRB: Brooktrout E1 solution does not answer inbound calls.



ID: ZTN1072

This Zetafax technical note applies to:

  • Zetafax 6 and later


Brooktrout device reports 'Unable to connect to remote fax (4, 34)' when dialling itself on a free channel or remote sender will receive an engaged tone.


The default BCHANMAP.CFG file is configured such that the Brooktrout drivers listen for incoming PRI calls starting with PRI bearer channel 1. If that channel is busy they try channel 2 then channel 3, etc. Some service providers configure their systems so that calls come in on bearer channel 31, and then channel 30 etc. This means that if you have all 30 PRI channels live, but have fewer than 30 Brooktrout channels connected to the system, incoming calls will be rejected.


The solution to this problem is to edit BCHANMAP.CFG so that the Brooktrout boards map to the top bearer channels.

This can be done by using a suitable text editor to edit \bfax\server\BCHANMAP.CFG, (where 'bfax' is the name of the directory where the Brooktrout ECC files are installed.):

You need to edit the second column of numbers in BCHANMAP.CFG so that instead of counting up from channel 1 it counts down from channel 31 (or one less than the number of lines you bought if you are using fractional PRI). For example, if you have eight channels attached to port B then need to change from:

# Created by Zetafax.

# Revision: A

# BoardType: E1


# port channel mvip_stream mvip_timeslot


1 1 6 0

1 2 6 1

1 3 6 2

1 4 6 3

1 5 6 4

1 6 6 5

1 7 6 6

1 8 6 7


# Created by Zetafax.

# Revision: A

# BoardType: E1


# port channel mvip_stream mvip_timeslot


1 31 6 0

1 30 6 1

1 29 6 2

1 28 6 3

1 27 6 4

1 26 6 5

1 25 6 6

1 24 6 7

NOTE: Bearer channels 0 and 16 are not used for calls.

Save the file, stop the Zetafax server and the BTNA service and then restart the Zetafax server. This will ensure that the BTNA Service is restarted with the new parameters.


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

Last updated: 22 June 2000 (GC/GW)

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