Topic: Hey Selintra! -couple of voip newbie questions

[kruhm]

I'm having trouble understading a few items about SARK/VOIP. If you could give a quick answer or point me to a link, I'd appreciate it.

Currently I have a traditional PBX attached to a PRI from the phone company. If I wanted to switch to a SARK system:

-does the SARK connect to the current handset/phones or do I have to replace them with VOIP sets?
-can the SARK interface with my current PRI or do I need a VOIP provider like BROADVOICE?
-if so, who do you recommend (Broadvoice, nufone, etc)?

Thanks in advance

[SARK devs]

Hi Kruhm,

Hope you are well.

You can run your existing phones provided they are regular RJ11 pots (i.e. domestic type) phones.  If they are digital then probably not.  To run pots phones you will need an IP or PRI channel bank.  Rhino do PRI versions, Multitech and others do SIP versions.  They aren't particularly cheap so it's usually easier to bite the bullet and order a bunch of SIP phones.  They work better than the clunky old pots phones and will probably work out cheaper in the long run.

SARK can interface to your existing PBX across the PRI.  Essentially you put a twin PRI card into the SARK box and then patch the whole thing in between your old clunker and the PRI.  This is kind of cool because you can keep your old PBX and use call-preselect to fling stuff out over VoIP if you wish.  You can also provide new services to your users from the SARK box; conference bridging, voicemail (if you don't already have it) etc etc.  You can also gradually bring SIP users in on the SARK to replace phones on the old clunker.  You'll need a small patch from us to make it work but it should be OK.  You should also check first that your old clunker can switch short dial strings (like 4 digit extension numbers) out over the PRI - some can't.

For Voip it's very difficult to suggest a carrier.  It depends entirely upon where you are geographically.  Some are good and some are, quite frankly awful. 

In the UK there are only really two carrier class VSP's - Gamma and Magrathea - and a couple of high quality resellers who run with them (Telappliant and Gradwell).  The rest are a bit of a mixed bunch, some good, some not so good. There's oodles of 'em out there who'll sell you call minutes at cut-throat rates but the jitter and poor termination rates usually come as standard.  - "He...o - Ca. .u. hea.  me?"  .



Kind Regards

S

[kruhm]

So I can keep my current telephone provider without changing to a VOIP provider. Great!

"SARK can interface to your existing PBX across the PRI."

I don't want it to interface with the old PBX. I want to kill the old PBX and replace it entirely (I can't find anyone who will work on it). I just don't understand/know how SARK interfaces with my current channelbank.

Or can I skip the channelbank setup and plug directly into the PRI port from the telelphone company?

Do you offer paid-for, hold-my-hand support?

[gippsweb]

As Jeff is probably getting a few long overdue zzz's at the moment I'll try and answer this one.

Selintra do have a support service in place for their boxes, at an extra cost of course.

As for the PRI bank, they should be able to plug a card into a sark box to allow you to plug directly in to your current channel bank or directly into the PRI.
(Jeff will no doubt correct me if I'm wrong as my PBX knowledge is limited and Tony our PBX guru isn't contactable at the moment).

[SARK devs]

yes, you can plug up directly to the PRI.  Asterisk works superbly with PRI.  We've done lots of em and they just run.  As long as your PRI has regular RJ45 outputs you can just plug up and go.  Older PRI's (at least in the UK) use twin BNC connectors.  If you have that kind of gear then you will need to ask your Telco to change the NTE for a new one, but that's all.

Yes we do paid support, that and selling Digium hardware is how we make our living.  We do complete remote installs and aftercare all over the World;  Asia-Pac, EMEA and the Americas.  We've had our dirty little paws on more asterisk systems than most.

Drop me a line at admin@selintra.com if you'd like to talk more about what you have and what you'd like to do.

Kind Regards

S

[gippsweb]

Isn't it like 2am or thereabouts, don't you ever sleep Jeff??

[SARK devs]

I'll sleep when I'm dead.

Truth is I tend to catnap rather than actually sleep.  It drives my family nuts but it's always been this way.   

We don't have much time during the office day to answer the contribs stuff so I tend to do it in the wee small hours.

Best

Jeff

[judgej]

...
SARK can interface to your existing PBX across the PRI.  Essentially you put a twin PRI card into the SARK box and then patch the whole thing in between your old clunker and the PRI.  This is kind of cool because you can keep your old PBX and use call-preselect to fling stuff out over VoIP if you wish.
...

This is something I am very interested in, and have not been able to find out any information on how to do it. I have a small PDX with twin POTS lines and one BRI interface card. Is is actually possible to insert the SME server in between the BRI interface of the PBX and the ISDN socket on the wall-box? If so, any ideas on what equipment I am likely to need?

I have purchased a Linksys SPA3102, which does the equivalent for the POTs (and an impressive little box it is too).

I would like to keep our PBX, but ultimately would like to be able to insert better control between the PBX and the POTs/BRI lines, allowing seamless interaction with VOIP. For example, if an incoming VOIP call could be fed into a PBX BRI channel, perhaps with a faked CLI number, then I could handle direct-dial of VOIP numbers through to individual PBX extensions.

[SARK devs]

Hello Judgej,

So...  You have achieved an interface using the 3102 but now you wish to do the same thing over the BRI interface - yes?  The answer is yes it can be done.  However.....

First, and please forgive me if I am telling you something you already know, ISDN Basic rate, unlike PRI, is asymmetrical.  In the same way as we have FXO and FXS signalling in analogue circuits, we have TE mode and NT mode in ISDN BRI.  They stand for Network Termination and Terminal Equipment (if memory serves).  Most devices run in TE mode.  The trunks on your existing switch are running TE.  In order to bridge between your PBX and the Network you will need two ISDN cards (or two ports) one running in TE mode (attached to the Network) and the other running in NT mode (attached to your existing PBX).

Fortunately, some cards can switch gender (those based upon the Colgne HFC chipset).  Junghanns cards can do this, as can most generic HFC offerings (if you can't get any, we supply them).  Moreover, the Junghanns cards can be specified with 2, 4 or 8 ISDN ports.  The next thing to bear in mind is that when you run an HFC card in NT mode, you have to run a special ISDN crossover cable.  This is NOT the same as a cat5 crossover cable and you'll have to make it up yourself (or have someone make it up fpr you).  Junghanns cards don't need crossover cables because, in true Teutonic fashion, they have on-board jumpers which will do the crossover for you.

Finally, you need to be able to specify NT or TE mode to asterisk.  If you are running vanilla asterisk then you can do it yourself.  If you want to run SAIL, then 2.2.1 can't do it (it doesn't have the mechanics to specify TE mode).   However, SAIL 2.1.15 mISDN could do it.   We fully intend to fetch the mISDN mechanics forward to 2.2 from 2.1.15 as soon as the OSLEC team manage to get OSLEC running with mISDN.    In the meantime, you can run 2.1.15.  It runs very well but has no advanced echo cancellation.  We run it here with a Junghanns QuadBRI card running all 4 ports in NT mode.  We use it as a low cost test-bed for testing our regular HFC releases.

Sorry for the essay.

Kind Regards

Selintra

 

[judgej]

Sorry for the essay.

No - thank you very much for the essay. You have explained a few things to me that a hundred Google searches left me none-the-wiser.

-- Jason