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VoIP T38 Fax reliability
by jrandall＠comwave.net Jan. 7, 2010

Jan. 7, 2010

Faxing over T.38 from experience has certainly been a better experience than over G711u bypass. Of course there are some implementations of T.38 that interoperate with each other better than others. My experience with AudioCodes, Linksys/Sipura, and Grandstream has been very positive. One of the common potential problems with either approach is the behaviour of the signaling in response to which end (caller, callee, or both) of the session is responsible for initiating the re-INVITE for T.38. When supporting wholesale customers it is not always possible to configure the behaviour of the ATAs/IADs and the only way to ensure fax will at least always be "detected" is to have one of endpoint gateways/ATAs/IADs detect fax as the caller and the callee. The next fun piece to tackle once that's configured is to ensure that all endpoints properly support handling SIP 491 Request Pending response codes to avoid a race condition which can cause INVITE "glare" if one endpoint is configured to detect faxes and re-INVITE for both caller and callee and the other is set to detect faxes and re-INVITE on either. Regards, Justin _____ From: voiceops-bounces at voiceops.org [mailto:voiceops-bounces at voiceops.org] On Behalf Of Ujjval Karihaloo Sent: Wednesday, January 06, 2010 7:01 PM To: voiceops at voiceops.org Subject: [VoiceOps] VoIP T38 Fax reliability I know this a thorn in everyones flesh, I would like to know of experiences with T38 Voip Faxing. We have had good and bad. Those that don't work just don't and they don't even want to troubleshoot and just switch over to an Analog line for Fax. We mostly use AudioCodes and Sipura T38 ATAs. Any of you folks do T38 and whats the experience like.

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Skype gateways? Anyone using them?
by jtodd＠loligo.com Jan. 6, 2010

Jan. 6, 2010

I've been asked to throw something out here on the list to see if anyone is using a Skype gateway of some sort. I know that quite a few people do trunk Skype into their existing TDM PBX platforms for connection to customer service lines, or for the odd road warrior who needs access to a DISA trunk. But is this widespread? Are the companies making the "hardware" units making reliable equipment? Does any carrier think that Skype calls through or into their network is a viable business in some way, or is it always a threat? Yes, Digium does offer a Skype software package that could be considered "competitive", but I'm actually somewhat interested to know if anyone is doing significant amounts of Skype trunking into their other TDM or VoIP networks. I'd welcome open discussion of this, since it's kind of an interesting operational question. If you feel like it, you can answer this short survey, too - http://bit.ly/skype-gateways http://www.voip-info.org/wiki/view/Skype+Gateways JT disclaimer: it seems relevant to say that this is usually my .sig: --- John Todd email:jtodd at digium.com Digium, Inc. | Asterisk Open Source Community Director 445 Jan Davis Drive NW - Huntsville AL 35806 - USA direct: +1-256-428-6083 http://www.digium.com/

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VoIP T38 Fax reliability
by carlos＠race.com Jan. 6, 2010

Jan. 6, 2010

Send and pray that what we say with faxing over voip lol. Carlos Alcantar Race Telecommunications, Inc. 101 Haskins Way South San Francisco, CA 94080 P: 650.649.3550 x143 F: 650.649.3551 E: carlos at race.com -----Original Message----- From: voiceops-bounces at voiceops.org [mailto:voiceops-bounces at voiceops.org] On Behalf Of Alex Balashov Sent: Wednesday, January 06, 2010 6:36 PM To: voiceops at voiceops.org Subject: Re: [VoiceOps] VoIP T38 Fax reliability On 01/06/2010 07:15 PM, Gabriel Kuri wrote: > It seems to be hit and miss, certainly not 100%, but better than > trying to use either PCMU or PCMA over the commodity Internet for > FAXing. PCMU/PCMA might work over a local private LAN with QoS enabled > and the jitter down to almost nothing. Agreed about T.38 vs. analog pass-through. > The biggest issue I've seen > with T38 is the ATA's inability to properly negotiate a Super-G3 fax > down to G3 or slower speeds. In our experience, you need to disable > the Super-G3 feature of the FAX machine to slow it down to either 14.4 > or 9600 and disable ECM. Many of the newer FAX machines have a "VoIP > Compatibility" mode which essentially slows it down to 9600 and > disables ECM. There's been an enormous explosion of Super G3 machines in the last few years; asking users to disable SG3 is not really tenable. Fax over IP is one of those things that, like anything else, can be gotten to work passably with enough spiritual commitment. But it's just not worth it. Hand the customers some resale analog lines or what have you and be done with it. -- Alex Balashov - Principal Evariste Systems Web : http://www.evaristesys.com/ Tel : (+1) (678) 954-0670 Direct : (+1) (678) 954-0671 _______________________________________________ VoiceOps mailing list VoiceOps at voiceops.org https://puck.nether.net/mailman/listinfo/voiceops

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Delay on RTP for Inbound Calls
by ujjval＠simplesignal.com Jan. 6, 2010

Jan. 6, 2010

Hi Guys; We have noticed that sometimes when calling into our DIDs (Level 3 DIDs), there is a 2-3 second lag. i.e. Cell phone caller (party A) calls into a DID (Party B) that is on our network (Broadsoft Softswitch), Party B answers and sayd 1,2,3,4,5 - but the Party A only hears 4, 5...The part i.e. 1,2,3 get cut off. Plus it is sporadic and difficult to reproduce, was wondering if folks have encountered this and any good troubleshooting techniques you can recommend. Ujjval Karihaloo

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Level3 voice rep
by carlos＠race.com Jan. 5, 2010

Jan. 5, 2010

Does anyone have a level3 tdm voice rep ? that they don't mind sharing thanks in advance. Carlos Alcantar Race Telecommunications, Inc. 101 Haskins Way South San Francisco, CA 94080 P: 650.649.3550 x143 F: 650.649.3551 E: carlos at race.com

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Toll free number search.
by mylists＠battleop.com Dec. 23, 2009

Dec. 23, 2009

I guess I am not using the correct key words trying to find this info out. I have a customer that's asking for a specific toll free number so I am trying to find out who holds a toll free number. The obvious step was to call it and see if anyone answers. That was done and it appears to be a non-working number. I am sure there is some way to find out who holds this number but seeing as how I have never had a need for this I don't really know where to start. Richey

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Toll free number search.
by carlos＠race.com Dec. 23, 2009

Dec. 23, 2009

Sms/800 holds the db but you might have to use a resporg todo the db lookup for you. http://www.sms800.com/ Carlos Alcantar Race Telecommunications, Inc. 101 Haskins Way South San Francisco, CA 94080 P: 650.649.3550 x143 F: 650.649.3551 E: carlos at race.com From: voiceops-bounces at voiceops.org [mailto:voiceops-bounces at voiceops.org] On Behalf Of Richey Sent: Wednesday, December 23, 2009 12:09 PM To: voiceops at voiceops.org Subject: [VoiceOps] Toll free number search. I guess I am not using the correct key words trying to find this info out. I have a customer that's asking for a specific toll free number so I am trying to find out who holds a toll free number. The obvious step was to call it and see if anyone answers. That was done and it appears to be a non-working number. I am sure there is some way to find out who holds this number but seeing as how I have never had a need for this I don't really know where to start. Richey

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10 digit craziness
by hiersd＠gmail.com Dec. 23, 2009

Dec. 23, 2009

For the good of the order... We just worked through an issue in which 10 digit domestic calls were being routed (correctly) as domestic but rated and billed (incorrectly) as international. 503-nxx-xxxx were rated for El Salvador, etc. We caught it pretty early, and the carrier fixed it for us. Still, it was a pretty interesting problem to work through, and something to add to your list of "things that can go wrong". Best, David

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10 digit craziness
by jrandall＠comwave.net Dec. 22, 2009

Dec. 22, 2009

Ouch! Yeah working with carriers the deal with both National and International traffic it's always best to stick with one of the below setups to avoid billing/routing issues of this kind: - 10D National Dialing with 011+CC-NDC+STNC for International - Full E164 (with or without the "+") for both National and International Helps preventing calls to Toronto avoid going our to Switzerland. Justin -----Original Message----- From: voiceops-bounces at voiceops.org [mailto:voiceops-bounces at voiceops.org] On Behalf Of David Hiers Sent: Tuesday, December 22, 2009 12:37 PM To: VoiceOps at voiceops.org Subject: [VoiceOps] 10 digit craziness For the good of the order... We just worked through an issue in which 10 digit domestic calls were being routed (correctly) as domestic but rated and billed (incorrectly) as international. 503-nxx-xxxx were rated for El Salvador, etc. We caught it pretty early, and the carrier fixed it for us. Still, it was a pretty interesting problem to work through, and something to add to your list of "things that can go wrong". Best, David _______________________________________________ VoiceOps mailing list VoiceOps at voiceops.org https://puck.nether.net/mailman/listinfo/voiceops

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Old code vs bold code
by hiersd＠gmail.com Dec. 21, 2009

Dec. 21, 2009

I've been snooping around our production systems, and the base code version for everything that we run in the call path is between 2 and 3 years old. It is patched to a fare-thee-well, and the stuff runs quite well. We use only top-tier vendors, yet can't recall ever being happy on code that is less than 1 year old. Too many bleeding edge bugs for my current medication level. How 'bout you guys? How long do you let a codebase steep before you're happy with running it in production? Thanks, David

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