UKVoIPTalk.com

yes, thats what it looks like...
[color=blue]
> Pacman wrote:[color=green]
>> Maybe its a basic question. But I am trying to find out:
>>
>> Is it possible to dial in using a modem to another Computer behind an
>> "VoIP only" connection?
>>
>> Szenario: home user with an internet contract that provides DSL. The
>> phone line bundled with the contract is established as VoIP. So no "real"
>> land line phone.
>>
>> Is it now possible to create a classic dial in to a server?
>>
>> Extension: would it be possible to do a classic modem-modem call back as
>> well?
>>
>> (all this at low cost - no cisco routers or something)
>>
>> I found some words like modem relay but I am not sure to be on the right
>> track.
>>
>> P[/color]
>
> Maybe I'm reading this wrong but why on earth would you want to attempt a
> modem connection using VoIP when the VoIP is already going to be on a
> broadband connection anyway?
>
> Anyway, the answer is you might be able to get a *very* slow modem
> connection working (14.4kbps at the most using normal g711 codecs) but
> even then it's likely to be unreliable. You'd also need to buy an ATA to
> connect the modem to if you don't already have one, although perhaps you
> already have a router with an ATA built-in since you've got VoIP with your
> Internet connection already.
>
> cheers,
> Paul.[/color]

I'm trying to do something similar and am struggling !

I have a bunch of dataloggers at remote locations with gsm modems. On
the PC at base I have standard analogue modem on a BT line, which I
use to download data and manage the loggers. I want to discard the BT
line and to see if I can do this operation via VOIP or another
internet based process. Download speed only needs to be 9600 (the max
speed for the GSM modems).

There are useful articles on the principles at [url]http://www.modemsite.com/56k/voip.asp[/url]
& [url]http://www.voip-info.org/wiki/index.php?page=Modem%20over%20VOIP[/url] but
I have no found any info on a practical "how to" solution. The
problems seem to be to do with the compression codecs used in VOIP
being designed for voice and not data - surely there is a software
solution somewhere ???

Any ideas/help would be appreciated

In article <9a2c1dd5-79bc-4581-9874-cee7bb2adb65@60g2000hsy.googlegroups.com>,
<tc@stoneblue.me.uk> wrote:[color=blue]
>I'm trying to do something similar and am struggling !
>
>I have a bunch of dataloggers at remote locations with gsm modems. On
>the PC at base I have standard analogue modem on a BT line, which I
>use to download data and manage the loggers. I want to discard the BT
>line and to see if I can do this operation via VOIP or another
>internet based process. Download speed only needs to be 9600 (the max
>speed for the GSM modems).
>
>There are useful articles on the principles at
>[url]http://www.modemsite.com/56k/voip.asp[/url]
>& [url]http://www.voip-info.org/wiki/index.php?page=Modem%20over%20VOIP[/url] but
>I have no found any info on a practical "how to" solution. The
>problems seem to be to do with the compression codecs used in VOIP
>being designed for voice and not data - surely there is a software
>solution somewhere ???
>
>Any ideas/help would be appreciated[/color]

If you can use VoIP, them you have broadband... If you have broadband
then you either have cable or ADSL, and if you have ADSL, then you need
a phone line - which you can use for a modem...

I'll assume you have cable and you want to save money by dropping the BT
line...

Modem and FAX data don't work well over VoIP because, while we humans
can ignore then odd click, packet loss, or duplication, a modem can't.
On top of that is the digitization of the signal - and if you compress
it with a lossy compression, then you can not reconstruct enough of the
modem signal at the other end to reconstruct the data stream. (Even if
the modem can actually recognise the resulting compressed noise!)

So far better to keep the PC at base with it's standard BT line and
modem to collect data from the remote sites - put ADSL on the BT line,
and use that to send the decoded data to other sites, as required.

How much data are we talking about here? If it's < 160 bytes at a time,
then why not send it as a TXT message? You could then have a GSM modem
on the PC, and from there send the data out via broadband (Cable,
I assume, since if you wanted ADSL, you'd have the phone line)

You could just try it and you might get away with it... Get an ATA
and a VoIP account with a geographic number - make sure the ATA is fixed
to use G711a and connect a modem to the ATA and see what happens ...

If you want to eliminate cables, get a VoIP provider that can give you
an IAX feed and get IAXMODEM -
[url]http://www.voip-info.org/wiki/index.php?page=Asterisk+IAXmodem[/url]

Your PC will need to be running Linux though.

Another way might be to get someone to run the "modem" for you at the
end of their VoIP connect - if they have a better than ADSL/Cable
quality connection... Then get that site to post the data to your
processing PC via the Internet... (Or have it processes at a remote site
doing this for you). However I'm guessing that as you want to dump the
BT line to presumably save £11 a month, you're doing this really on the
cheap, so who knows if you'll get anyone to let you do this who might
charge you less than £11 a month. (But if this is an option, drop me an
email!)

Gordon

Thanks for that Gordon - So it may be just possible in principle, but
it is unlikely to be that good. This is more or less what i gathered
reading around the subject, but v helpful to have it explained so
clearly.

I'm binning BT anyway, so I better just get another dedicated fax/
modem line with the new supplier. The risk of data loss is way more
than £11 pm !

TC

[email]tc@stoneblue.me.uk[/email] wrote:[color=blue]
> I'm trying to do something similar and am struggling !
>
> I have a bunch of dataloggers at remote locations with gsm modems. On
> the PC at base I have standard analogue modem on a BT line, which I
> use to download data and manage the loggers. I want to discard the BT
> line and to see if I can do this operation via VOIP or another
> internet based process. Download speed only needs to be 9600 (the max
> speed for the GSM modems).
>[/color]

Why don't you use a GSM modem at the local end?

Old Nokia phone + cable.

I think you will get faster initialization times on calls with it being
GSM to GSM.


----

Other long term option would be to swap to dataloggers using GPRS. Then
they can be always online sending info to you over the internet. I know
a company that does a lot of work in this area.

Tim