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Obsolete Releases => SME VoIP (Asterisk, SAIL etc) => Topic started by: Teviot on December 13, 2008, 06:10:04 AM
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I would like know if it is possible to get a PSTN LandLine Caller ID to come though instead of the asterisk account number coming though.
Is it possible to change thing so the caller's ID comes though? If so, could I be pointed in the right direction?
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Sure, do you have the service enabled? Some PSTN providers will charge extra for the service.
In South America and Parts of Europe I had to buy an adapter as well to convert the CID to American Standard (My boards were bought in the U.S.)
Thanks,
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Well, first of all, Caller-ID is almost always a chargeable feature so you'll need to speak to your PTT about renting it if you don't already have it.
Next you'll need to get your asterisk hardware device to recognise and read the CLID. In general, TDM telephony is delivered in one of three ways, (irrespective of where you are in the World); Analogue; Basic Rate Digital or Primary Rate Digital. For digital circuits, since they are all pretty much the same, Caller-ID just happens so you don't need do anything other than read it off the screen. However, for Analogue, it is a complete bugger's muddle because there is no standard for delivering CLID over an analogue circuit. As a result it varies from country to country and PTT to PTT. Sometmes it even varies within the same PTT (e.g. Virgin media here in the UK). As a result, some asterisk hardware (particularly at the cheaper end) won't recognise CLID in all countries. The most common CLI transmission method is Bellcore (developed at Bell Labs) and most hardware will happily see it - I believe with Bellcore that the CLID arrives between the first and second ring but I may be wrong on that so don't quote me. Here in the UK, BT use a variation of ETSI which sends a regular BT "K-Break" polarity reversal to signal the arrival of the CLID (just before the first ring) so you need harware which can sense the K-Break (Digium cards will, many others won't).
Anyhoo, suffice to say that it changes from country to country. You will find pages and pages of "folklore" on the main VoIP websites as to how you should set up your card or your ATA for your country or region, some of it is good, some of it is complete bollocks but that's the internet for you.
The most important thing to be aware of with CLID and Asterisk is that the Zaptel drivers were written primarily for Bellcore and then later modified to suit other standards. As a result, when you turn CLID sensing ON in asterisk it will ALWAYS hold the call for the first two rings, irrespective of how the CLID is actually delivered.
This can be a real problem for customer facing organizations with hard SLA's. For example, we have a Vehicle Rental customer who has a stated SLA (in their brochure) that 90% of all calls will be answered within 4 rings. Unfortunately, they only get to hear it at ring 3 with Asterisk CLID turned on! Of course if they did the sensible thing and converted to Digital lines than the problem would go away.
Sorry for the essay, I've just had a big breakfast and I'm in contemplative mood. :)
Best
S
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selintra
Thank you yet again. Upon reading your reply I was able to identify the setting in my SPA3102 and go straight to it to change it. Caller ID now works.
Thanks you very much