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ISDN Trunk Setup

Simon P

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I'm new to the forum so please be gentle!


Currently in the process of choosing a new phone system and very much like the features and ease offered by SNOM.


I've had a good search of the manual, wiki, forums etc but would very much appreciate some clarification regarding setup for ISDN trunks. We have 2 BRI channels.


Do I just need to install a suitable PCI card into my box? I've seen mention of various adaptors etc but I'm not sure if these are necessary. All calls will be over ISDN.


Many thanks.

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You have essentially two choices here.


First choice is to put everything into one box (e.g. snom ONE mini), then you have to use Sangoma cards with NetBorder Express.


The second choice is to use a seperate gateway, then you have two boxes, but full choice in term of gateways. Especially in the (German) ISDN that can be an advantage, because there are a lot of local extensions for ISDN. Even devices like the AVM Fritzbox can be used (http://kiwi.pbxnsip.com/index.php/AVM), however the poor echo compensation at that time suggest to take a product with explicit echo cancellation (e.g. BeroNet, Patton).

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  • 5 months later...



if I have an ISDN line with 3 MSNs (name them 398330, 398331 and 3983302), then, when a call comes in, the ISDN protocol signals which MSN ist actualla bein called. Depending on the MSN, I would like to assign the call to different extensions or groups.


How do I do that?


The only way I see today, is to define 3 SIPs on my gateway and create 3 trunks on my Snomone. My gateway then routes given incoming calls to given SIPs and so the given Snomone trunks can react differently.


So the question from emuessig is actually: is there a way to avoid 3 trunks and instead use the MSN as a variable to arrange routing in the Snomone?


Of what help would it be to assign MSNs to extension? The link to the orginating MSN has gone lost in the meantime?





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thanks for the clarification, Norbert. That's what I want to do.


To stay with Norberts sample: I have now created a LAN phone on my FritzBox which

listens to MSN 398330, 398331 and 3983302.


In snomone I created a trunk which registers this LAN phone.

I created three extensions "40 398330" and "41 398331" and "42 398332".

Then I tried to find out what to put in "Send call to extension:"


- when I put "40 41 42" snomone will always select extension 40

- I then tried "398330 398331 3983302" which failed with "unknown extension" error


How do I need to setup the trunk in snomone to route to different extension

according to the MSN?

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There is a description on the Wiki on how the PBX routes calls to the right extension: http://wiki.snomone.com/index.php?title=Inbounds_Calls. The country code setting (http://wiki.snomone.com/index.php?title=Domain_General_Settings) is also important; the PBX uses it to interpret numbers that are not clear as global nombers (for example 398330 is translated into +4930398330).

So in short words: (1) Make sure that your domain has the right country code and the right area code. (2a) Either use the alias names of the accounts (e.g. "40 004930398330") to listens to what account has which telephone number. or (2b) use the trunk regular expressions to for example extract the last 2 digits from the MSN and use that as extension number.

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  • 2 weeks later...

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