[MLB-WIRELESS] Free P2P phones will pressure telcos
Ryan Abbenhuys
sneeze at alphalink.com.au
Wed Nov 12 22:25:53 EST 2003
Would yourself or a representative from your company be interested in
giving a presentation at a Melbourne Wireless meeting at some stage
perhaps? Followed up with a TIB deal for those interested?
>So that I'm not howled down by all and sundry this is a FYI post not a
>"shameless" plug.
>
>I work for a company who distribute IP telephony units aimed at the
>home user. These units work through the USB port of Windows (only -
>damn) computers and even though they come with their own software they
>work with Skype.
>
>With the supplied software all units generate their own ring and dial
>tones, have an international prefix for telephone numbers, and are
>registered with a central server in Taiwan. We've tested them with
>broadband as well as dial-up and in both cases I would give the quality
>of the call an 8 (if PSTN is the benchmark of 10). Making calls is
>simply a case of picking up the handset and dialling.
>
>They come in three flavours: A PSTN/IP phone model that allows you to
>connect an analogue handset to it, as well as a PSTN line. Nothing
>really fancy about this unit but you can attach a cordless analogue
>handset to it, and attach it to a PABX for incoming and outgoing IP
>telephone calls.
>
>The next model is a handset type for your travelling person.
>
>The third model has all the same features as the first, but it also
>allows call hop off so you can call from the IP network to PSTN and
>vice versa, and call forwarding features. We've tested call forwarding
>to PSTN and mobile telephones and again the quality is about 8.
>
>The only costs associated is the hardware, they don't charge for the
>calls.
>
>The only downside is that it is a "closed" network, ie you can only
>ring another one of the units.
>
>So that it doesn't come across as a plug I'll leave out the name of the
>equipment, and supplier. If people do want more info you can e-mail me
>off-list.
>
>Regards,
>
>Damian Halloran.
>
>
>On 12/11/2003, at 4:06 PM, Tony Langdon wrote:
>
>>> Well, it would partly work, but you wouldn't be able to dial
>>> (afaik) as the
>>> soundcard input doesn't detect DTMF (afaik). You'd still need
>>> to dial via
>>> the software phone.
>>
>> Hmm, perhaps the IRLP style approach (but with phone handsets and
>> hardware
>> based line simulators, instead of radios) is the way to setup a VoIP IP
>> ohone network. The idea is actually quite simple in concept.
>>
>> 1. Define a numbering scheme. This can be a simple "flat" scheme
>> like ICQ
>> (basically the ham VoIP apps work this way), or something more complex
>> using
>> international prefixes and the like. I prefer KISS, we're not billing
>> here.
>> :-)
>>
>> 2. Setup some form of address resolution. This could use DNS
>> (12345.freeipphone.org, etc), or some specialised server based scheme
>> (the
>> ham systems have their own schemes for address resolution).
>>
>> 3. Define some sort of hardware interface to connect the phone to the
>> PC.
>> The interface would need to generate ring voltage (80V AC - oscillator,
>> audio power amp and a transformer should do), and all the necessary
>> voltages
>> and signalling to make an ordinary POTS handset work. The interface
>> could
>> also include a DTMF decoder chip so it can perform this function as
>> well.
>> Alternatively, you could write this function into the software (I have
>> seen
>> both approaches used, but the hardware one works best). Hardware
>> decoding
>> also makes it easy to script in special functionity that can be
>> accessed
>> whenever the phone is off hook, regardless of whether it's on a call
>> or not
>> (a la IRLP).
>>
>> 3. Start with some existing piece of open source software. Hack it
>> to work
>> with the above interface for call establishment and termination, so
>> all the
>> user has to do is treat it like a normal phone - just pick it up and
>> dial
>> (or answer). For our application, probably one of the SIP based VoIP
>> packages would be most appropriate.
>>
>> 4. Build on extra functionality outside the package. Shell scripting
>> can
>> work well here, and make the package very "hackable". That's one of
>> the
>> strengths of IRLP in the radio world. If the functionality is not
>> there,
>> chances are you can add it in. :)
>>
>> Of course, the hardest part will be getting the hardware out there.
>> Now, if
>> any of us is involved in electronic manufacturing, that would help.
>> Good
>> thing is it won't need Austel/ACA approval, as it's not interfacing to
>> the
>> phone line, just your PC. :-)
>>
>> Might also be a good project for mags like Silicon Chip. :)
>>
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>
>--
>Damian Halloran B Comp
>P: 03 8430 8691
>M: 0419 308 036
>F: 03 9417 1848
>E: damian at phit.com.au
>
>
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