[olug] Level3 and fax modems over VOIP

[K.J. Kirwan]

I didn't know this was a problem, so I'm glad you said something. 
I hope others will be able to add some useful information. 

Using a modem (recent modems, 56k, even 33k, etc.) on VOIP I could 
see maybe being a problem because they are designed to use as much 
of the theoretical bandwidth of an analog voice line as possible. 
Whereas VOIP is designed to simulate an analog phone line while 
using as little bandwidth as possible. So I'll let that go for now. 

But the fax problem surprises me. I thought faxes were all running 
14400/bps max, and that seems pretty low by recent standards. 

It would be interesting to try a pair of US Robotics' so-called 
"V.Everything" modems on VOIP.  Maybe test & review some networks? 

Have you tested what LightYear.net said? 
What does your VOIP equipment do with faxes and modems if you 
connect it all together in the same room on a private LAN? 

This sounds like it has more to do with latency and packet priority than 
bandwidth.  Maybe analog modems and faxes are intolerant of varying 
time delays since delay seldom changes on an analog line? 
So vendors charge more for higher packet priority to fix the problem, 
or say no, they don't support faxes/modems?  Of course, I suppose the 
vendor might also say, "Hey, it's called VOIP, not MOIP or FOIP!"

It's an interesting problem, please keep us posted on this. 

K.J.


Rob Townley wrote:
> You may be aware that faxing or using a modem over a VOIP line
> generally does not work, and if it does, it probably does not work
> well.  Even Vonage does not work well.  I discussed this with
> LightYear.net, ( a VOIP provider that provides Omaha telephone #s )
> and they said the hardware they sell and the SIP protocol used both
> are capable of faxing over VOIP, but that their provider Level3 does
> not support it.
> 
> Can anybody confirm that this really is a problem with Level3?  If you
> got faxing & modem communications to work, did you have to pay extra? 
> Anybody know if Vonage uses LVLT.net?
> 
> p.s. I used iConnectHere.com because it was $8.95/month and after
> several months could pretty much get single page faxes to work and
> much later multiple page faxes, but it was not all that reliable.  I
> decided it was worth the trouble.
> 
> p.s.s. I am a stockholder and needless to say i was very disappointed
> that lvlt.net and level3.com were down some today!
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