Ring Detect Problems With Voice Modems And Voip Analog Lines

[Guest GAMNONS]

Hello all,

I seem to be having problems with ring detection on my VOIP phone line (a residential VOIP box that provides the actual physical line) with fax/voice modems, which prevents usage of VoiceGuide on this line.

I've already contacted the VG tech support and was told that voice modems are unreliable vs professional cards such as Dialogic, but the fact is that two out of four modem cards I have tested detect ring just fine, but the problem is that these two modems are fax only and thus cannot support the voice features VG needs such as CID capture and audio playback. All four modems detect ring without problem on a standard PSTN line.

Since I've been requested by VG support to continue discussions here which I agree is better for the benefit of the VG community, I'll re-post with hope that other users might have found success with other types of voice modems or firmware/driver updates. So here is a description of what I've done:

 

I have tried 4 modem cards, two Voice modems (Creative Modem Blaster and and a PINE brand, both based on different ESS chipsets) as well as two DATA/FAX only cards (Best Data and Aztec brands). I have tested them with the Windows Hyperterminal program, to be sure the problem is the modem's ring detection and not their drivers or VG.

 

What I see is that with a standard PSTN line here, rings are detected on all 4 modem cards (by the modem outputting a "RING" message to the screen in hyperterminal), while with two different VOIP phone lines I have here (a Siemens and Motorola VOIP boxes) only the fax modems detect the ring while the voice modems ignore the ring and don't display any message. It might be an ESS chipset quirk or maybe typical of voice modems, I don't know yet.

 

Trying to analyze the cause for the problem, I put an audio monitoring device on both lines and it seems that's there's definitely a difference between the analog ring signals on the different lines. I have captured waveform pictures as well as audio recordings of the two to demonstrate what I mean (3 rings total + callerID data between the

first two rings) and can upload here if requested.

 

What can be seen is that the PSTN ring signal is one-second length bursts of a 25Hz continuous sinusoidal signal with 3 seconds pause in between the rings, while the VOIP box's ring signal is two seconds length with 4 second pause in between, seems stronger and is actually made of a higher frequency signal (about 2KHz) chopped into small chunks at about 40Hz rate. For clarity, I've attached some images to demonstrate what I've described.

 

My guess is that some voice modems firmware cannot adapt to the different cadence of the VOIP ring. The exact way the high voltage ring signal is created (continuous 25Hz vs chopped 2KHz) shouldn't make the difference because it's rectified and converted to DC pulses anyway in the modems analog ring detect circuit.

There is also a difference in Caller ID data amplitude, but that doesn't seem to cause problems with caller ID boxes I tested so I doubt it matters either.

Also, a Samsung standalone multi-function printer/copier/fax works fine with both types of line rings, including auto-answer mode which is based on ring detection.

 

I am aware that most of the info I supplied here might be beyond the scope of most software/integration guys in this forum, but hopefully, even part of it will ring familiar (pun intended...) and will enable me to use VG.

 

So have any you encountered similar problems with voice modems and have found a solution such as specific good voice modems or firmware/driver updates?

Thanks and cheers to all.

[SupportTeam]

Are you able to use a softphone with your VoIP service provider?

If you are able to use their service from a softphone then you would be able to set up VoiceGuide v7 in VoIP mode to work with the VoIP service directly.

suggest contacting VoIP service provider for softphone configuration instructions. Most VoIP providers allow this.

[Guest GAMNONS]

Hello and thanks for the prompt response and new idea.

I have tried asking their tech support re direct connection to their servers but they didn't have a clue...but I didn't use the term "softphone", so if you provide me with a link to info regarding softphones for Windows PC's (XP) or windows mobile/iPhone/Android, I can ask my provider again.

Cheers.

[SupportTeam]

One popular VoIP SIP phone that has been around for a long time is SJ Phone:

 

http://www.sjlabs.com/sjp.html

 

Another one is X-Lite:

 

http://www.counterpath.com/x-lite.html

 

 

There are many others...

 

http://www.zoiper.com/softphone/classic/

 

http://www.portsip.com/dlphone.htm

 

http://www.icanblink.com/download.phtml

[Guest GAMNONS]

Thanks for the info, I'll check it out.