SIP Trunk provider recommendation needed.

Unanswered Question
Jan 29th, 2010
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Hey guys,

I am looking for a good recommendation for a SIP trunk provider which meets the following requirements:

1. Must support G.729 and G.711 codecs

2. Must support T.38 fax

3. Must allow SIP authentication over the Internet

Our situation is unique, in that we provide mobile emergency communications into Mobile Command vehicles via satellite.  We have good (in the Satellite world) data rates starting at 3x1 Mbps, and the majority of our clients only need a few lines when deployed on an Emergency.  However, our Satellite ISP is charging an arm and a leg for voice termination.  We have been setting our clients up on NexVortex SIP Trunks, but it is possible that they do not support T.38 (as I found out this weekend).  Web searches have revealed little substantial info about this.

While sitting in on the "Good morning Techies" webex yesterday, I was able to see the advantage of a managed SIP trunk service versus an unmanaged SIP trunk, but am not sure that I have much control over this without paying a ton of money for voice termination by the Satellite ISP.  Our Satellite traffic lands in Richmond, CA, so anything that might fit the above requirements in that locale would be great.

FWIW, I DO have the ability to order a backhaul from the ITSP to the Satellite Ground station if need be.  Thanks for your recommendations,


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Maulik Shah Fri, 01/29/2010 - 09:51
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  One option to alleviate the fax requirement maybe to use a email to fax service as you will find that doing fax over an unmanaged satellite link using T.38 will be cumbersome as the delay / jitter will cause issues (its not the overall bandwidth but the time interval between packets). See if the link below helps (note no recommendations as we have not tested or worked with these ITSPs):

I would have suggested Skype for SIP but that does not support fax yet.


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