Not receiving most in-bound faxes on NEC UNIVERGE SV8100 attached fax machine 2

[John in Texas]

We have a NEC UNIVERGE SV8100 PBX running WebPro 9.50 (North America) and DT300 Series phones. One of our SLT ports is connected to a high-speed Konica-Minolta printer/scanner/fax machine, bizhub 552. This setup has been in place about 7 years with all working pretty well. We send very few faxes and those are sent on the Konica-Minolta bizhub 552 manually. Recently, about half our in-bound faxes do not get received. Senders call and complain that the fax seems to be accepted but then ends abruptly without receiving any pages. I called Konica-Minolta support for assistance, but they say that their fax modem is working perfectly from their remote tests. Using another SLT port and attached HP printer/scanner/fax, we can always successfully send and receive faxes between the two fax devices. I tried an in-bound fax service from FaxZero.com and I always receive emails stating that the faxes failed because the phone line was unexpectedly disconnected. When I connect an analog phone to the Konica-Minolta fax line, I can hear a clean dial tone. I can make outbound calls and do not hear any static. I can also receive in-bound calls to the analog phone fine. We then purchased a new Canon laser fax and connected it to the analog line that went to the Konica-Minolta. Unfortunately, we get the same bad, fax receive results. This makes me think possibly something in our NEC PBX has deteriorated. We have not made changes to the NEC software in months. I would appreciate any suggestions on how to better test and resolve the in-bound fax issue. Thank you!

 

[belevedere]

You failed to mention what kind of trunking you have, and if that has changed. POTTS, PRI, SIP?

 

[John in Texas]

My apologies belevedere. We are using a PRI T1 consisting of 24 channels. This has been the setup since the NEC PBX was installed 7 years ago. Of course, our upstream providers could have made changes I am not aware of.

 

[belevedere]

Replace the FAX machine with a SLT and test. Do you have the same issue?

 

[John in Texas]

When I place a SLT in place of the fax machine, I can receive calls and make calls every time with no static.

 

[daddybadger]

Had a problem like this with a customer and a panasonic on pri. Put it down to the channels needing rebuilding on the network side and since the carrier wouldnt be doing that ended up with a fax to email service.

 

[John in Texas]

Thank you daddybadger for the information. I hope it doesn't come down to having to do the same here as you had to do.

I read that the typical analog line should have a reading of 45 to 48 mV DC. I put a volt meter across the punch down posts for the UNIVERGE SLT configured line and the reading was a "1". I tried another meter and got the same reading. Apparently, the output of the NEC SV8100 is not the same for a POTS analog line. I did this test with the fax machine connected and disconnected. The readouts were the same. The reason I tried this was because we can send and receive faxes internally through our PBX, one fax machine to another, but cannot receive faxes from outside numbers. that caused me to think perhaps internally, any drop in line voltage would be less noticed than when someone is sending us a fax from the outside. I wonder if our PRI provider made any changes that might affect our ability to receive faxes? Outside senders simply report that all seems normal during the fax send transmission until about 40 seconds, then transmission stops for no apparent reason.

 

[daddybadger]

How about.... point your fax DID to an slt extension with a fwd all to your fax or send it to an internal extension and transfer internally to the fax, does that work?

 

[John in Texas]

What an interesting idea daddybadger! If I understood you correctly, I had an outside fax sent to my desk phone's DID, which I had forwarded to one of our fax phone numbers. Unfortunately, the fax did not go through. I called my desk phone's DID using my cell phone and heard the fax modem try to sync, so I know the forward was working. I opened a problem ticket with our PRI provider last night in hopes they can see something wrong with our ability to receive faxes. I informed them we can send out fine and we can fax to each other internally through our PBX fine as well.

Somehow, a one page fax came in this morning from a local pediatrician's office for an employee. So, I tried having an outside fax service send to the same fax machine and no luck. Ugh!

 

[OzzieGeorge]

Faxes "train" for speed, if your carrier has introduced some sip trunking between you and the rest of the world, the speed you can send/recieve a fax at will have greatly reduced. It could well be that the pediatricians fax will only work at a slower speed and so your fax "trained" down to that speed and so it went through. Speak to your fax supplier and see if there is a way to force it to send at a slower speed and if there is, test using the slower speed. If this works, simply leave it at the slower speed. Don't quote me but I think 9600 is the speed for fax over VoIP whereas most faxes will work at 14400.

 

[John in Texas]

Thank you OzzieGeorge for the idea on fax speeds. Just to make sure I have communicated clearly, we can send on any of our fax machines and they are received 100% of the time by the intended other party. We can send and receive 100% successfully from one fax machine on our PBX to another that is on our PBX. I can control the TX speed of the fax, but I have not found a way to control the RX speed. It is the receiving of faxes that we have the problem and I would guess that 90% or more do not complete. By that I mean our fax machine's modem begins the normal process of answering, fax synchronization for about 1 second, then what appears to be a time out occurs at about 40 seconds and no fax or part of a fax is printed at our end. The senders to us tell me they see an error stating that the connection has prematurely ended. We connect our fax machines to a NEC UNIVERGE SV8100 CD-8LCA 8 analog SLT interface blade. It has a solid red LED on it, but has since it was installed 7 years ago. It also has a blinking green LED on it. I do not believe the red blinking LED has caused the fax receive problem since that light has always been on and I do not know how to debug it to find out why it is on. The vendor that installed it told me the red light is not a problem. I'm not sure if that is true and if new errors have occurred.

It seems that the number of faxes that we do not receive increased about 3 months ago. This is based on feedback from those that normally receive faxes. I asked our vendor that provides our PRI if they made any changes that might negatively affect our ability to receive faxes. They say they are researching it and will get back to us. I am unfortunately not optimistic. One of our employees that used to work in a NOC said that he recalls hearing of a problem like ours that he believed occurred when a PBX based fax machine would fail trying to receive from an outside PBX based fax machine. He mentioned this Friday when I told him that we received a fax from the small doctor's office. He said their fax machine is probably hooked up to a POTS line and that is why it came through. Please let me know if any of this rings a bell. Thank you for your efforts to assist!

 

[OzzieGeorge]

Do you have any sip extension licenses on the system? if you do, try a product called Ventafax, there is a free "home" download that is good for a month and it works registered as a Sip extension, if you can receive to that, problem solved, if not push back on your provider. it may also be worth trying an ATA on a cheap sip service to see if that works and if it does, migrate the number to that service!

Just a disclaimer, I have no relationship with Ventafax, I found it by accident looking for a fax solution to offer with a 3CX PABX and was impressed with it's simple solution to a problem presented by fax over Sip!

 

[John in Texas]

Thank you for another idea OzzieGeorge. The link above provides a picture of our registered NEC UNIVERGE licenses. I'm not seeing something specific to sip extension licenses. Would I need that software to work with Ventafax running on a Windows PC with a fax modem plugged into one of our SLT ports? Could I just take the current RJ11 cable going to our Konica-Minolta fax/scanner/printer and connect it the Windows PC with a fax modem and Ventafax software? Physically, I know I can do that, but is the sip extension license needed to facilitate getting this setup to work? I wonder why our current setup is working without the sip extension software? Sorry to be so naive.

 

[daddybadger]

I came across today in the manual (as I was looking at a bt versatility that was up the swanny) something about 3.1khz which allows data transmission. Can't find any settings on the nec so suspect it's definitely something to do with the carrier.

 

[OzzieGeorge]

I believe Ventafax will work with a modem connected to an ATA or an SLT port but you should check out their web site.

 

[John in Texas]

And the answer is: I spoke with our PRI provider for the first time directly on Friday and it turns out that a few months ago, they migrated us to a new platform called BroadSoft and since no one at their end had documented that we use some lines for faxing, they had not applied the T38 codex needed for faxing to the line. That is when the problems began. I am glad that we can now receive faxes.

Thank you to daddybadger, OzzieGeorge, and my long time go-to-guy belevedere for trying to help me! May you all have a great week!

 

[OzzieGeorge]

So as I said, "if your carrier has introduced some sip trunking between you and the rest of the world" and they had! Good to know you have resolved this! and others may find this in the future so thanks for posting your resolution!

 

[John in Texas]

Yes OzzieGeorge, your suggestion and my simply wanting some help from our PRI provider caused me to pursue talking with them about the problem and a final resolution. Thank you for the idea. When I first tried to contact them, I was only able to talk with a 'problem documenting person' who in turn talked with an actual technician. That is where the breakdown in the communications occurred as what was relayed did not accurately describe the problem. I then elevated the problem to a manager and only then was I able to talk directly to a technician that quickly recognized the problem and corrected it in less than 20 minutes. Some companies are getting too large for their own good, which negatively impacts the customers.