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Re: Does IP telephony suck?

In article <48a72e8f$0$2928$fa0fcedb@news.zen.co.uk>,
Klunk  <givemespam@wibblywobblyteapot.co.uk> wrote:

>Thanks for taking the time to run through that with me Gordon. It's the
>first USENET post that I've cut, pasted and saved for a number of years.
>
>Being ex-BT the bit that bewildered me was this dual fibre thing only
>delivering a 2m link when I know we used to knock the same thing down a
>couple of pairs of copper. I can't see the benefit in using the fibre in
>the first place when you factor in the cost! One of the guys in the place
>was saying that they tried to get their DSL down the fibre too and BT
>laughed at them, telling them it could not be done. I'm sure that a fibre
>link is plenty capable of speed - oddles of it in fact. My best guess is
>that there is no 'product' that matches what the company I am working for
>wants.

BT want to put fibre everywhere, but tehy do have some odd rules - it's
probably to do with the competition rules set by Ofcom/whatever. It
wouldn't surprise me if they were using less than 1% of the capacity of
all the fibre they've laid....

>I get your point about the reliability of VOIP. Clearly there is going to
>be a big difference with good hardware, a fibre ISDN 30 and dedicated
>equipment. Much more than a DSL line, a PAP2 and a wonky PSU ;-)
>
>I've got the bug over this whole thing. My interest in telecoms goes way
>back and it captivates me. I'm going to have a 'play' with Asterisk. I'm
>a Linux bug anyway, so I don't have a steep learning curve. It's going to
>come down to basic concepts. I've read that there are hardware issues
>with PCI latency, but I don't know how old the article was. Other than
>the Box Gordon, what am I going to need to set up a little 'test'
>Asterisk system? Say I have 2 X PSTN on the wall + 2 X Sipgate and wanted
>to put in 5 extensions. I guess I'm going to need some 'compatible'
>phones - hows and what's I am not clear on. I guess I will also need some
>form of card to convert the incoming PSTN. How this will all bolt
>together, and be 'cheap enough' so that her indoors will let me play -
>whilst giving me a useful 'primer' is yet to be seen.

Look for trixbox or pbx in a flash. They're mostly "canned" versions
of Asterisk + Linux, but might get you going. Failing that, see if your
Linux distribution has packages, and if all-else fails, try
www.asterisk.org and compile it from source...

Hardware wise, look for a TDM400 card with 2 x FXO modules. (You
might want to try the OpenVox clone cards as they are cheaper). I use
http://www.voipon.co.uk/ for most of this stuff. Stick an FXS module
on it too to connect up a local anlogue phone (cheaper than an ATA but
you'll not get much change from £220 for the card + 3 modules)

(US terminology - FXO's connect to the "Central Office" ie the Telephone
Exchange, FXS connect to Stations - ie phones)

If you just had one line, then you might find an X100p card (or clone
card) on eBay for £20 or less though. I don't think it's good to have 2
of them in a PC though.

You won't have PCI latency issues on a relatively new motherboard, but
the TDM card prefers to have an IRQ all of it's own. (Although I'm told
the newer TDM410 boards are much better in this respect) I haven't done
an analogue install for a month or so, so not looked at the newer card
yet, but I have an openVox card I'm experimenting with...

You might also want to download "the starfish book" and read it - Search
for "Asterisk - the future of telephony" - it's in PDF format now.

Cheap & basic phones are Grandstream BT200's, but the display is numeric
only. They are in the "fisher price" range, but I've deployed quite a
few of them with good results.

Have fun!

Gordon

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