Fax digital line question

[mascan42]

I have a customer that is getting intermittent distorted incoming faxes on their C353. They have VOIP in their office, but there is a lot of confusion about whether the fax line is analog or digital. At first they said it was digital, then they said it was changed to analog, then they said it was analog all along, and their provider shows no record of any kind about this line. Is there any way to tell for certain whether the line is digital or analog?

[nmfaxman]

For faxes to work on VOIP the machine has to be IUT .37 or .38 compatable.
I tell my customers to have a dedicated land line for their fax to save headaches.

[mascan42]

For faxes to work on VOIP the machine has to be IUT .37 or .38 compatable.
I tell my customers to have a dedicated land line for their fax to save headaches.

I realize this, but is there any way to tell whether this is a dedicated analog line or not? After changing their story 3 times, I can't trust the customer to tell me.

[kingarthur]

I would take a small desktop portable fax m/c & plug it in, it will only work on an analogue line. then you will have your answer.

[HuronMan]

I realize this, but is there any way to tell whether this is a dedicated analog line or not? After changing their story 3 times, I can't trust the customer to tell me.

I went and bought a cheap analog phone for this reason. If it's a digital line, there should be no dial tone. If it is digital, a digital-to-analog converter can be used. I have several customers using voip lines w/ converers and most work well.(except for 420, 421's,)

[blackcat4866]

Make a Tester

Build yourself a simple phone line tester. ~ Total Cost $35.00
Attach a D'Arsonval movement VOM to the back of a fax handset. wire the input=female RJ11 red & green wires to a DPDT switch (to reverse the polarity), then to the VOM/handset. This is not terribly high tech, but you can identify a really bad, out of specs phone line.

Plug the phone cord into your new tester. Check these voltages:

On Hook: -48 VDC (-42.5 to -56.5 VDC), 90 VAC
Off Hook: -10 VDC (-8 to -12 VDC), 8 VAC
Ringing: peak 125 VAC (110 to 137 VAC)

The polarity only matters so that your meter will deflect the correct direction. All modern faxes correct their own polarity.

If the line is out of specs, check the same voltages at the demarc (where the phone line comes into the building). If voltages are still out of specs, its the local telephone provider. If its OK at the demarc, you can be sure its the PBx.

It sounds complicated, but with the tester and a little practice you'll be out of there in 10 minutes with proof it's not your machine. That can be hard to come by.

You'll spend $200 or more for a commercial tester with these same features.

[emujo]

Just some additional info in KonicaMinolta and VOIP. Km says the fax may work with some minor changes, but they DO NOT support it. You cannot get any support if it does not work. EMujo