Overview

You may have switched the phone lines on the fax server from POTS lines to Digital lines, and now larger incoming faxes (1 MB or more) are failing and cutting off.

Solution

This has been reported when using Brooktrout TR1034 cards, but the issue was apparently related to the provider of the digital lines, not with the fax card. Although the examples and logs in this article come from the TR1034, the context may also be applied to other devices.

You'll be looking for indications of Handshaking errors and MPS/MFC signals not being completed, which would point to an issue with the line provider.

Start by trying to match one failure with a No loop current error code on the Brooktrout logs:

"info ","BrkLine02","SYS#: 02/25 11:01:33.78 2[2,4] < (12) ECC (08) EVENT (10) LOOP_CUR_LOST (13) BCHANNEL_ID [00: Fix Uns Byte Unitless] 00"
"info ","BrkLine02","fax_dev_c::receivefax _ BfvFaxRcvPageTiff failed [res.status = 4] [res.line_status = 3] [HNG_NO_LOOP_CURRENT (3)] [Hangup: No loop current. (3)]"
"info ","BrkLine02","fax_dev_c::receivefax _ ending receive process"
"info ","BrkLine02","fax_dev_c::receivefax _ calling BfvFaxEndReception"
"info ","BrkLine02","fax_dev_c::receivefax _ BfvFaxEndReception failed [res.status = 4] [res.line_status = 3] [HNG_NO_LOOP_CURRENT (3)] [Hangup: No loop current. (3)]"
"info ","BrkLine02","--------------------"
"info ","BrkLine02","Fax results:"
"info ","BrkLine02"," Pages: 17"
"info ","BrkLine02"," Bad pages: 0"
"info ","BrkLine02"," Results for received page 1:"

The faxes may be failing because the MPS Multipage signal command from the sender is not received, thus ending the fax. FaxMaker must receive the MPS, to which it responds with an MCF Message Confirmation, allowing the next page to be transmitted.

Each section below represents one successful fax page:

"info ","BrkLine02","SYS#: 02/25 10:21:53.83 2[2,4] MPS Multipage signal"
"info ","BrkLine02","SYS#: 02/25 10:21:53.92 2[2,4] MCF Message Confirmation"
"info ","BrkLine02","SYS#: 02/25 10:22:02.67 2[2,4] recv'd data 8048"
"info ","BrkLine02","SYS#: 02/25 10:22:07.71 2[2,4] recv'd data 16096"
"info ","BrkLine02","SYS#: 02/25 10:22:12.96 2[2,4] recv'd data 24144"
"info ","BrkLine02","SYS#: 02/25 10:22:19.98 2[2,4] recv'd data 32192"
"info ","BrkLine02","SYS#: 02/25 10:22:20.42 2[2,4] recv'd data 32554"

"info ","BrkLine02","SYS#: 02/25 10:22:21.51 2[2,4] MPS Multipage signal"
"info ","BrkLine02","SYS#: 02/25 10:22:21.59 2[2,4] MCF Message Confirmation"
"info ","BrkLine02","SYS#: 02/25 10:22:30.09 2[2,4] recv'd data 8048"
"info ","BrkLine02","SYS#: 02/25 10:22:35.64 2[2,4] recv'd data 16096"
"info ","BrkLine02","SYS#: 02/25 10:22:42.45 2[2,4] recv'd data 24144"
"info ","BrkLine02","SYS#: 02/25 10:22:48.57 2[2,4] recv'd data 32192"
"info ","BrkLine02","SYS#: 02/25 10:22:48.77 2[2,4] recv'd data 32324"

We see above that the MPS was sent from the fax sender and FaxMaker responded with the MCF. Both of the above pages succeeded. After that, the MPS Multipage signal command from the sender is not received in order for the next page to begin to transmit. Instead, we see a no loop current disconnection:

"info ","BrkLine02","SYS#: 02/25 10:22:50.62 2[2,4] < (12) ECC (08) EVENT (10) LOOP_CUR_LOST (13)
 BCHANNEL_ID [00: Fix Uns Byte Unitless] 00 (0B) IDLE_CAUSE [01: Fix Uns Short Unitless] 0010 (45)
 IDLE_SUBCAUSE [01: Fix Uns Short Unitless] 0000 (2D) IDLE_CAUSE_LOCATION [01: Fix Uns Short Unitless] 0000 (15)
 AOC_TYPE [00: Fix Uns Byte Unitless] 00 (16) AOC_CURRENCY_MULTI [00: Fix Uns Byte Unitless] 00 (17)
 AOC_CHARGE [02: Fix Uns Long Unitless] 00000000 (12) PORT_ID [00: Fix Uns Byte Unitless] 03"

Under these circumstances, the line provider would have to review their logs to see why they are not sending the MCF:

• Has the sender stopped sending the MCF?
• Or has the provider received it but failed to forward it to the fax server?

On the FaxMaker's side, the recommendations to try improving this situation are:

• Upgrade FaxMaker to the latest release, which also upgrades the Brooktrout drivers. There were known issues when using older Brooktrout drivers.
• In the FaxMaker Configuration Tool, go to all fax lines under Lines/Devices and ensure they are all set to 200x200.