I've been using VOIP for a while now, but there is a possibility I may have
to do some ISDN audio sessions soon.
ISDN is a bit pricey for the amount of time I'd use it. Is it possible to
run an ISDN session over some kind of ata type device? So virtual ISDN here
to real ISDN somewhere else...
> I've been using VOIP for a while now, but there is a possibility I may have
> to do some ISDN audio sessions soon.
presumably by this you mean "plug in some proprietary codec unit that
talks to another one at the other end"
> ISDN is a bit pricey for the amount of time I'd use it. Is it possible to
> run an ISDN session over some kind of ata type device? So virtual ISDN here
> to real ISDN somewhere else...
the short answer is probably "no". VoIP is packetised audio, ISDN is a
circuit switched system. A VoIP to VoIP call using a high bandwidth /
quality code is probably the closest thing if you can persuade the
other end to accept it.
Barney wrote:
> I've been using VOIP for a while now, but there is a possibility I may have
> to do some ISDN audio sessions soon.
>
> ISDN is a bit pricey for the amount of time I'd use it. Is it possible to
> run an ISDN session over some kind of ata type device? So virtual ISDN here
> to real ISDN somewhere else...
>
> Cheers,
>
> B
"Barney" <barney_dot_mcgrew@blueyonder-dot-co.uk> wrote in message
news:HgmKg.12620$r61.12042@text.news.blueyonder.co .uk...
> I've been using VOIP for a while now, but there is a possibility I may
> have
> to do some ISDN audio sessions soon.
>
> ISDN is a bit pricey for the amount of time I'd use it. Is it possible to
> run an ISDN session over some kind of ata type device? So virtual ISDN
> here
> to real ISDN somewhere else...
>
> Cheers,
>
> B
>
>
In principle this should be OK, but there are two problems you would need to
worry about: -
Throughput class. Actually an issue from X.25 days, what it means is that
you have to be guaranteed a minimum amount of bandwidth an a second to
second basis.
Transit delay - all the nodes and packetisation mean that it can be a long
time before data from one end pops out at the other. Not only that but the
end station will need to keep a reasonable size buffer in case of glitches,
especially on long haul.
"Tim" <nutnews@kooky.org> wrote in message
news:44fc4015$0$640$bed64819@news.gradwell.net...
> Barney wrote:
> > I've been using VOIP for a while now, but there is a possibility I may
have
> > to do some ISDN audio sessions soon.
>
> Do you mean a wideband audio ISDN session for something like a radio
> interview?
Indeed but it won't be used that often, hence why I'd rather try something
IP based than the expense of getting ISDN installed.
"R. Mark Clayton" <nospamclayton@btinternet.com> wrote
>
> In principle this should be OK, but there are two problems you would need
to
> worry about: -
>
> Throughput class. Actually an issue from X.25 days, what it means is that
> you have to be guaranteed a minimum amount of bandwidth an a second to
> second basis.
>
> Transit delay - all the nodes and packetisation mean that it can be a long
> time before data from one end pops out at the other. Not only that but
the
> end station will need to keep a reasonable size buffer in case of
glitches,
> especially on long haul.
Assuming that the potential problems could be overcome, is there any
equipment on the market to achieve it?
"Barney" <barney_dot_mcgrew@blueyonder-dot-co.uk> wrote in message
news:7d0Lg.13552$r61.2479@text.news.blueyonder.co. uk...
> "R. Mark Clayton" <nospamclayton@btinternet.com> wrote
>>
>> In principle this should be OK, but there are two problems you would need
> to
>> worry about: -
>>
>> Throughput class. Actually an issue from X.25 days, what it means is
>> that
>> you have to be guaranteed a minimum amount of bandwidth an a second to
>> second basis.
>>
>> Transit delay - all the nodes and packetisation mean that it can be a
>> long
>> time before data from one end pops out at the other. Not only that but
> the
>> end station will need to keep a reasonable size buffer in case of
> glitches,
>> especially on long haul.
>
> Assuming that the potential problems could be overcome,
Former yes, latter not really*.
> is there any equipment on the market to achieve it?
Barney wrote:
> "Tim" <nutnews@kooky.org> wrote in message
> news:44fc4015$0$640$bed64819@news.gradwell.net...
>
>>Barney wrote:
>>
>>>I've been using VOIP for a while now, but there is a possibility I may
>
> have
>
>>>to do some ISDN audio sessions soon.
>>
>>Do you mean a wideband audio ISDN session for something like a radio
>>interview?
>
>
> Indeed but it won't be used that often, hence why I'd rather try something
> IP based than the expense of getting ISDN installed.
>
There are wideband audio codes available for IP telephony.
These give similar quality to the ones used on ISDN
terminals. A proprietary one is used by the Skype service,
which is relatively easy to set up - the studio end would
need to interface to a PC sound card.
Note that any public Internet connection is liable to
impairment, given there's no dedicated circuit like ISDN.
Barney wrote:
> Indeed but it won't be used that often, hence why I'd rather try something
> IP based than the expense of getting ISDN installed.
All the Snom phones will support wideband audio using G.722 at 64kbs of
audio.
But I suspect that your application requires some other wideband codec
running at 128kbs.
You would need compatible equipment at both ends.
What do they have at the other end? I don't know of any IP to ISDN
gateways that will pass through G.722 audio.
If you are trying to avoid the cost having an ISDN line installed, can
you not use somebody elses? If it was for audio, I'd try a local
radio station - if audio quality is important then a sound proof room,
decent microphones etc come into play.
> "Tim" <nutnews@kooky.org> wrote
>
> But I suspect that your application requires some other wideband codec
> running at 128kbs.
>
> You would need compatible equipment at both ends.
>
>
> What do they have at the other end? I don't know of any IP to ISDN
> gateways that will pass through G.722 audio.
Usually this would be over 2 B channels at 128kbs MP2.
> If you are trying to avoid the cost having an ISDN line installed, can
> you not use somebody elses? If it was for audio, I'd try a local
> radio station - if audio quality is important then a sound proof room,
> decent microphones etc come into play.
Bizarly it'll be a Radio station I'd be connecting to :)
"Barney" <barney_dot_mcgrew@blueyonder-dot-co.uk> wrote in message
news:vViLg.13995$r61.3869@text.news.blueyonder.co. uk...
>> "Tim" <nutnews@kooky.org> wrote
>>
>> But I suspect that your application requires some other wideband codec
>> running at 128kbs.
>>
>> You would need compatible equipment at both ends.
>>
>>
>> What do they have at the other end? I don't know of any IP to ISDN
>> gateways that will pass through G.722 audio.
>
> It would probably be conecting to a Prima CDQ or other such device:
> http://www.isdnaudio.com/musicam/cdqprima.html
>
> Usually this would be over 2 B channels at 128kbs MP2.
64kBs is normally OK for news, 128kbs should be OK for normal talking, but
will be well shy of the quality required for music (CD = ~700kbps), although
it compresses well e.g. MP3.
>
>> If you are trying to avoid the cost having an ISDN line installed, can
>> you not use somebody elses? If it was for audio, I'd try a local
>> radio station - if audio quality is important then a sound proof room,
>> decent microphones etc come into play.
>
> Bizarly it'll be a Radio station I'd be connecting to :)
>
> B
>
>
ISDN over IP 
Linear Mode
