I have a site that has two POTS lines that I will be using a UC320W and an SPA8800 to provide phone lines to a trailer in a quarry via a wireless connection. This setup works except that I have trouble receiving faxes from some fax machines. I'm guessing this wouldn't be much of a problem for the customer except for the fact that one of the machines that we are having trouble receiving from is the main fax machine in their main office.
Anyway, the main site fax machine is a Canon Laser Class 700 (actually a 730i I believe) fax machine and the fax that's connected to the VoIP is an HP LaserJet 3015. I actually got a fax through on Friday for the first time but, in order to make it work, I had to tweak the settings on the main office fax machine. Basically, I lowered the maximum speed to 9600 baud and I turned off ECM. Unfortunately, although this was great as a test, it's not a real fix. Obviously, they aren't going to be able to control all the fax machines that send faxes to them.
So my question is, is there a way I can configure the UC320W or the SPA8800 so that it forces the handshake with remote devices so that they will link up at 9600 baud and without ECM? Please note that I already tried setting the receiving fax machine to those parameters but the best I could do was No ECM and No V.34. My understanding was that those settings would give me what I wanted but, instead, I got the same communication errors I had started with.
Thanks for your answer. Actually, the fax machine is connected to an SPA8800. The UC320W is on the other side of the connection. The whole point of this setup is that there isn't a way to hookup the fax machine directly to a POTS line.
There isn't any infrastructure to do it. For the most part, the faxing works just fine. From what I can determine, there is a problem between Canon fax machines and VoIP-connected fax machines in general. I was able to get faxes to go through by tweaking the setup on the Canon but I would rather tweak the config on either the UC320W (which I guess is not possible) or on the SPA8800 (which I hope is possible).
So, to revise the question, is there anything I can do on the SPA8800? As for official support, I was told that this was a fairly typical configuration when I called for reseller presales support. From that I gather that this is at least "unofficially" supported and I hope that, maybe, someone has some insight.
The only option that can be tweaked for FAX is whether or not to use T.38 FAX protocol. Since you aren't using SIP trunks, the setting doesn't apply. The FXS port just appears like a line coming from the telco to the FAX machine. The FAX machines will negotiate the best speeds and settings at the call setup based upon the line quality at call setup. The challenge you face is that the line quality may change in the middle of the call and drop the FAX call. FAX and modem calls are already pretty sensitive to line quality characteristics. Packet loss or jitter doesn't have to be very high for the FAX to lose the carrier tone. Since you are running this over a wireless connection the call is more likely to see packet loss, delay, etc. The call may sound crystal clear to the human ear, but the machines are a lot more sensitive.
Hopefully, this helps put some perspective around your scenario.
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