Multiple DID formats in same trunk

FreePBX Providers
1

So, I have a strange problem to solve. We have a customer whose ITSP does not do DID normalisation before passing call to trunk.

ITSP sends DID in SIP To: field in one of following formats:

To: <sip:[email protected];user=phone>       
To: <sip:[email protected];user=phone>               
To: <sip:[email protected];user=phone>       
To: <tel:+49123456789>

What would be the most elegant solutions to get DID from To: in same context?

Obvious solution - to change an ITSP - is not an option in this case.

2

AFAIK there is no elegant solution. You will need to write custom dial plan to normalize the formats.

Use the context from-pstn-toheader in extensions.conf as a guide. Put a modified version of that, named e.g. from-pstn-normalize-did, into extensions_custom.conf, then change the context for your trunk to from-pstn-normalize-did.

You don’t have to worry about tel vs. sip or what comes after the @, but you do need to properly handle the case where the @ is not present.

Also, if you have DIDs in other countries from the same provider, you might see e.g. 0033123456789 for a Paris DID, which your dial plan will have to normalize.

3

Perhaps ‘cut’ on @ and select the last 9 digits from field 1

[custom-get-did-from-to-header]
exten => 1,n,Set(realdid=${SIP_HEADER(To)})
exten => s,n,Set(realdid=${CUT(realdid,@,1)})
exten => s,n,Goto(from-trunk,${realdid,-9})
4

thanks for suggestion, but not all of formats have @. Also, numer is not 9 digits necessarily.

5

I was afraid that would be the answer.

6

If there is no @ then field 1 is everything, -9 selects the last nine digits of field 1. which matches everyone of your examples.

7

True, but Germany has variable length numbers and DIDs in different cities would likely have different lengths. Also, if the OP has DIDs from other countries, length would obviously vary.

8

However, this is good idea. I will strip > first, then match against @. Then strip everything from beginning to :.

9

You can then cut on : and work with field 2. an expanded version of the from-pstn-e164-us modified for Germany would be a good place to start, selectively remove the prefixes appropriately to leave just the ‘national’ number,

10

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