atcomsystems.ca/forum Forums TDM Business Telephone Systems NEC Telephones & Systems Head banger

This whole thread is making me a little nervouse and sounds like issues that I get with another system with the same software. Flacky DTMF reciever settings.

Check MB 80.03.01 and see if the DTMF settings for stations is set to 0~25db
I have found a few here set to -15 ~ -470 causing problems..

The DTMF recievers are on the CPU card, and they are actually DSP chips. The CPU II has 32 DTMF recievers built in to the DSP.

One thing that sounds suspicious is that these Canon fax machines may have a setting for DTMF send timing and someone set it to something else not knowing what they set.

The DTMF send should be at least set to 80-100MS length and atleast 80MS interdigit time.

If this is the case and when the machine autodials out by dialing 9 then the rest of the digits it may be going so fast that the DSP is missing the second digit.

Try and manualy dial on the fax machine if it will let you do it.

I been told digi grabbers are not 100 percent accurate but when I was testing I had the tester on the dmarc and heard on the speaker of the digi grabber dial tone, DTMF and at the same time I heard the DTMF I watch the numbers come up on the display and they matched to what I dialed on the fax. I made about 20 test calls with the digi grabber and it showed every time the exact digits dialed from the fax.

maybe adding a pause(usually redial button)right after the dial "9" or trunk access code before inputting the number to be dialed could help.

Dan
How far the faxes are from the pbx?
can you connect them directly to the MDF?
Or
Do you have the long line interface "4LLC" cards installed in your system?
If yes try to use it for your faxes and test out.

We have connected the faxes straight to the MDF vie cross connect from dmarc to station cable, again the faxes do not fail at this point.

About the dial 9. That is how the system was set up and install, when this problem started few weeks back we had them enter pause after the 9, this didn't work. We than program the station ports per NEC to seize the line pool when fax goes of hook.

Dan S

Dan
That points out to the line impedance of the pair of wires going to each fax.
I may suggest to use 2 pairs for each fax instead of the pair, this will reduce the line resistance and improve loop current

Lee,

This office is brand new. Cat 5e cable was pulled for voice and data. I can't see this being cable issue.

Canon L120s use "Super G3" modems (V.34 fax protocol). Are the other "good" fax machines equipped with standard G3 modems, or with "Super G3" modems?