I have a customer, that has Their CEO in an office at a different Service Provider, Than his Company.

When he tries to fax, He will get the Tones from the other Fax but he will not be able to send the Fax.

This happens sometimes and sometimes not.

He has no problem making fax calls to other people.

The company has no problem recieving or sending faxes from other places.

Does anyone have any Clues as to what is happening.


Thanks,

Rusty

From your scenario the only thing I can see is the feature group trunks between the two providers.

Are these two fax machines ext of a PBX? Some cut the signal too low to work. Other systems can reduce the data flow to the point it won't work. Are you actually routing thru the public network or a private net?
If you "hear" the fax tone, maybe the level isn't high enough to latch the connection.
If it works to any one else, it has to be something common to the two locations.

Somttimes if you change from 1 Telco provider to another. They do not set it up so you can call lines in the original provider. It is a programming error. It has to do with number portability. It happens all the time for me between McLeod and SBC.

Good Luck!!

I had that same scenario occur at one of my customers out of the blue. Messed with it and messed with it for six weeks between SBC & CBeyond. Have seven other fax machines working at the main location with no problems on a FXII using IST ports thru a T1-PRI. Finally put that problem fax on a POTS line and haven't heard anymore. Moved the fax to another port, had SBC bring in a new loop, put the fax straight out of the switch, tried four other fax machines of different brand. This definitely whooped me and that doesn't happen too often.

I read something about a SLIC 40 the RBOCS use. 40 channels out of a T-1 pipe!! Depending on the electronics old or new, problems will occur. Maybe one of the other members can elaborate in this regard.

You read my post in VOIP Voice codeing option. The SLC40 was not modem frendly because it used G.726 coding. They were all replaced in the eightys. They were never used for SWITCH to SWITCH transmision. There are carrer problems that can cause modems not to work between switchs but I don't have time now to explain. She Who must be obeyed throws a fit if she can't serf the next. Here is a hint, B8ZS or AMI.

https://www.sundance-communications.com/forum/Forum30/HTML/000005.html


[This message has been edited by RedTail (edited April 02, 2005).]

I have had the same problem using Panasonic equipment with analog devices (fax, credit cards, and modems)working through the service unit. It only happens on the old WECO central offices. The DMS central offices works just fine. Put them on a POTS and they work fine. There has to be something the provider isn't doing.

Why your FAX won’t work on a T1 (not PRI ISDN).

You have a T1 into you PBX, voice calls are not a problem, but you can’t send a FAX. The T1 that you are leasing from the LEC is terminated into a Digital Crossconnect System (DSC) at the CO. The LEC uses the DCS to connect the T1 channels to CO carrier channel banks with FXO channel units. This takes the digital channels to analog to connect to the CO switch ports (POTS).

T1 coding has two options ESF/SF (SF is listed as D4 on some test sets) B8ZS/AMI. If the ESF/SF options at each end of a T1 do not match the system will not sync up and the T1 will not work at all. T1 transmission requires at lease a 17% ones density to keep sync. G.711 coding of voice is rich in ones. Data can have a high number of zeros causing a carrier system to have a low ones density. To overcome this B8ZS was introduced. Any time a channel has all zeros; Binary 8 Zero Substitution (B8ZS) will replace the channel with 4 bits with 2 bipolar violations. When the equipment at the other end of the T1 detects the B8ZS code the equipment will replace the four one bits with all zeros.

B8ZS/AMI option must match at both ends of the CO DCS to carrier channel bank. When the DCS is optioned B8ZS and the channel bank is optioned AMI, voice will work ok but Fax’s will fail. This is difficult for the CO to find. If your PBX lines are spit between banks and only one is optioned wrong, sometimes you can send a FX sometimes you can’t, depending on witch co line you uses.

Moore to come.