An article I read recently on tcpmag.com
If purchased second-hand, this may have the potential to be cheaper than an ISDN simulator which can be horribly expensive.
Has anyone used a setup such as this with Cisco routers and can you provide any info on what type of functionality I should be looking for in a PABX for use in this situation?
~Brad
Yes, and it works perfectly
checkout the pbx4linux project ==>
Polleke -
This is an interesting suggestion - one I hadn't thought of. Having read the pbx4linux documentation, it looks as though I'd want to use ISDN modems which can act as NTs - I assume they'd present an S/T interface.
Do you have any idea whether this interface would differ between countries? (I'm in Australia, but a lot of cards are being sold secondhand throughout Europe)
~Brad
They are full NT2 compliant, which means it is an ISDN switch (as the name says PBX per definition) Indeed the WIRING used in the states is that on the customer side they have a U bus to connect to, whereas the rest of the world uses an S bus. U bus(4 wires) and S bus(2wires) ARE completely different wirings.
ISDN is an open standard, you can find plenty of information about around the internet, and i would suggest you go find that information yourself, so you'll learn the most of it, and be an expert then ;-)
Now, back to the Cisco matter .... Cisco sells routers with BRI having a U OR S/T bus, you will need the S/T ones. (or you would need a complex setup having CSU/CSUs to convert the signaling between U and S bus)
As far as i know, in australia they use S/T as CPE on the user side, so that wouldn't be a problem. About the "extra" inter switch-S signaling there are indeed a lot of different variants on the protocol, but that isn't a problem either since the PBX4linux can handle most as it is CCIT compliant. On the cisco side, one can set the switch-type to basic-net3 to use the european variant (others work too, but can be more complex since you might need to setup spids on both sides then)
Special Remark: If you by NT-capable cards, BUY the Cologne Chipset ones, the others suck! They cost about 20 euros each
Do not underestimate ISDN signaling, it is a lot a more complex than ethernet is for example. You might be in for a lot of reseach to do, but finaly you will have learned a lot of the internals in the end. In my opinion, it's worth to do it. (Expect about 2 or more weeks to get it working)
Good luck mate
It's been discussed here (the idea of using PBX cards for ISDN). in fact, I believe there was a post with step by step instructions using a German based PBX card (using an ISA slot)
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