In article <8qSdnbgXqYPCtEzanZ2dneKdnZydnZ2d@bt.com>,
R. Mark Clayton <nospamclayton@btinternet.com> wrote:
>
>"Michael" <kj@nvb.com> wrote in message
>news:3Rfzj.61968$os2.5833@newsfe3-win.ntli.net...
>> Folks
>>
>> I run a voip line on the end of a cable connection from Virgin, and I
>> fully understand that the system works as the cable is 'always on'.
>>
>> What I don't understand is ..... others, who do not have 'always on'
>> cable, use VoIP ..... but how?
>>
>> My Mum for example, uses (as it happens) AOL for her Internet -and it
>> a dial up broadband system. How could she use VoIP - would she have to
>> leave her connection to AOL on 24/7?
>>
>> Sorry for being so thick.
>>
>> Regards
>>
>>
>> Mick
>>
>> --
>>
>
>It doesn't have to be "always on", just when you want to use it or take
>calls - a bit like my girlfriends mobile.
>
>It is possible to VOIP over an ISDN connection, but I never tried it. The
>quality would probably be similar to PSTN, but not as good as raw ISDN.
>
>It was possible to VOIP over dial up, but as you can imagine the quality
>would be poor.

I've managed to have a successfull VoIP conversation over a shakey 33.6K
modem connection using the GSM codec. I imagine it might have been a
shade better using g729... Latency was a bit high (as ping times are
over dialup), but other than that it was "usable"...

If you can get both channels of the ISDN line up, then running a full
bandwidth codec (g711) over it via SIP or IAX should't be an issue at
all. Bit of a waste of the lines though, but if you had free Internet
connectivity over it, it might be better than paying BT ...

>Perhaps someone can tell us if you can VOIP over 3G and how many channels
>you need, bear in mind though that the network providers will intentionally
>impede this working easily.

I've had a colleague call me via VoIP and a 3G connection. Bit laggy,
but otherwise OK. Not had a chance to try myself yet. Maybe this weekend
I'll have a play...

Gordon