Tech Support Forum banner

what causes the fax to be distorted?

10K views 3 replies 4 participants last post by  Gary R  
#1 ·
Hi, I am not sure if this is the right subforum, but this is an issue with our fax line and I think it is somehow related to our internet connection. So we have comcast business, with 4 phone lines and one fax line originating from the comcast modem (so I guess they use a VOIP kind of technology?). the fax line then is connected to our physical fax machines. My guess is at some p

For about a month now, we have been getting faxes that come out distorted, missing lines or even missing half a page, the fax page looks all crumbled up etc. We also have the same problems with some of the faxes that we sent-that the receivers can't read them. We called comcast three times and when the techs came, they said their only job was to make sure there is a dial tone on our fax line (which there always is) and they blamed our fax machine. However, we can print from the fax machine with no problems, and we actually switched to a different fax machine to test it out and have the same result so I don't think it's a problem with the machines. We can also scan and email documents fine using these machines. I got comcast to give us a brand new modem and it didn't help either (the modem is a technicolor CGA4131COM).

I called the phone people (the ones who set up the phone and fax lines inside the pharmacy for us) and sent them the messed up faxes and they said it doesn't look like something they can fix and it's most likely comcast's issue.

My guess is there is an problem somewhere with the decoding of the fax signal, and the more complex the fax image is, the more distorted it would come out. Also, the issues seem to happen more often if we receive/send to a digital fax vs a physical fax line.

Right now we are puzzled of what to do to narrow down where the problem is or who to actually call. Any insight is greatly appreciated!
 
#3 ·
I can give you some random ideas, but not sure how much I can help troubleshoot this over the internet. You may need a local telecom company, more experienced than the one you're using, unless someone else has a better tip.
  • Sounds like you have regular digital voice telephone service with Comcast, not a VOIP system. And digital voice can be hit or miss with fax machines.
  • Get a regular old telephone & a new cord (not a cordless phone or one that requires a power cord) and plug it directly into the modem for your fax line (or try the other phone lines, too). Any problems making or receiving a voice phone call?
  • Connect the fax machine directly to the modem with a new telephone cable - no other splitters, jacks, etc. Run a test fax back and forth with someone. Still having quality problems?
  • If this machine has a menu, go into the fax settings page and see if you can reduce the baud transmission rate. If it's set to 28.8, try the next setting below that and test a fax. It may run slower, but it may also print out correctly.
 
#4 ·
Distortion of an image sent by a fax machine usually come in 4 various forms ...

Vertical Black Lines through image .... caused by dirt or debris getting into the light path between lamp and document

Horizontal Black Lines through image .... caused by lamp flickering due to faulty lamp or faulty power supply.

Vertical Elongation of image .... caused by incorrect feeding of documents due to dirty or worn document feed roller(s)

Vertical Compression of image .... caused by incorrect paper feed, due to dirty or worn paper feed roller(s)

Any other kind is likely to be caused by external faulting, and the fact that you have changed machines and have had the same problem occur, would tend to confirm that your problem is external to your fax machine.

Unlike e-mails which are sent over the internet, faxes are sent over a telephone line, and that line must not be used for anything else, and should preferably not be routed through any kind of switchboard or other external device, since fax modems are sensitive to outside interference.

It's impossible to say with any kind of confidence exactly what may be causing the problems you're describing, but by the sound of things it may well be due to the way your fax line is connected into the outside phone network.

Do you have a direct line to outside that you can test it on ?