[Gta04-owner] Invitation to indicate interest in next batch of GTA04A5 boards

Dr. H. Nikolaus Schaller hns at goldelico.com
Tue May 21 12:17:44 CEST 2013

Hi Sven,

Am 21.05.2013 um 11:33 schrieb Sven Dyroff:

> Hello Nikolaus, 
> >> b) Make a little board equipped with the modem so, that it can be connected 
> >>    to the modem connector of this GTA04A5. 
> >> 
> >> c) Offer the handheld variant of the GTA04 ("OpenPhoenux 3704") in this way. 
> >>    There should be enough place within the case in order to do so. 
> > 
> > Originally we had experimented with modems from Telit which have such B2B connectors. 
> > But there was simply no space and there was no connector that we could have used for 
> > the antenna (you can't have RF signals go over the same type of connectors as the 
> > digital signals). So we did choose the OPTION GTM601 which is a LGA soldered to the 
> > PCB. 
> If you put the OPTION GTM601 on a separate board designed by yourself, you're free to choose any connector that seems appropriate to you. In particular you can use three connectors instead of only one: 
> a) Digital control and audio signals, that means the link to the GTA04 board. 
> b) Power. Perhaps even spend the modem its own power supply (controlled by the appropriate GPIO), so that you can connect this board directly to the battery. 
> c) Antenna. In particular you can connect the antenna directly to this board. There's no reason why the antenna should be connected to the GTA04 board in case that the modem is located on its own board. 

Well, the easiest interface for this is using USB... has power and data. Can multiplex sound-data with data-data.

> > 4. you can't develop such protocols and test them on the real air waves. I.e. you need 
> >   a network simulator e.g. from Rhode&Schwarz. Or buy a Ferrari from the money you 
> >   need to invest. 
> You're only talking about the situation within Europe. I don't think that anyone will say anything iin case someone makes developments on real air waves who is located in Siberia or deep outback of Australia or something like this. Who knows where all the possible interested developers live? 

All countries in the world have a quite strict radio regulation since almost 100 years (ITU).
> > So if you organize to develop and certify such a device, we will happily integrate it 
> > into a future GTA0x. 
> That's what I wanted to hear.  :-)) 
> > 5. to legally operate such a device you need a licence and certification. Expect an 
> >    amount equivalent to several Ferraris to finally get through this process... 
> Ooops.   :-(( 
> Someone out there who could donate us some Ferraris in order to do the needed certification... ? 

Yes. But let's drive them for some days before we exchange them into money.
The key problem in getting certification is that not only the radio emissions must match, but also the protocol must pass all tests. This is a very high requirement for the firmware. I.e. it does not work with a "let's fix that later" attitude typical in open source. And finally the organization asking for certification must fulfill some requirements (paperwork), i.e. everything during development must be documented and
traceable, ISO9000 etc.

Therefore I am quite happy that we can buy complete modems where others have done that for us...

> > 2. LTE protocols are not easily written in one weekend. Expect a project with first 
> >    results after at least 2 years, maybe 5. 
> > 3. at that time there will be 5G 
> That's not a real argument. IIUC GTA01/GTA02 made it for 2G at a time where 3G was already up to date. Currently we even don't have an open source 3G modem. So I suggested 4G just for the reason to overjump 3G. If we have an open source 4G modem, we can overjump 5G again and begin to develop 6G, directly...   ;-)) 

Well, nobody has started to develop anything for 3G yet, although the hardware is already available... So I am not sure anyone is capable of jumping on the 4G or 5G train. It appears to be similar to the PowerVR/SGX reverse engineering project. The dream and the hardware is here, but nobody has had success yet.

This is not a technical issue, it is IMHO more a problem of society in general. It may appear easier to buy something closed at 200 EUR than to learn how to open it.

> > I don't want to discourage you to develop an open source LTE modem. 
> > 
> > But there are some things to consider. 
> > 1. you need a baseband chip. MAX2580 and MAX2553 look good - but it starts with the 
> >    datasheet being available on request only. This means that you have to convince 
> >    them that you are a customer with big quantities so that it is interesting enough 
> >    for them to talk to you. 
> It's clear that I'm not in the position to do so. But perhaps I didn't express clear enough what my intention is: 

We aren't either :(

> You heavily asked for more developers. You wanted to hear unexpected ideas. You're asking for more orders for the GTA04A5. I tried to show you an easy and cheap way, how a simple modification of the layout of GTA04A5's plate and of advertising strategy could open a perspective to a possible new

Well, this change isn't cheap and easy, because the GTA04A5 + Option Modem becomes thicker and does no longer fit into the GTA02/4 case. Even if we make a new case, it will become more ugly.

And, for development of an open 4G board it would be easier to make some sort of development board (not a complete device) having (extra) battery, antenna and USB connectors. And a RF/Baseband chip + some ARM processor or FPGA with integrated ARM. Maybe 10 x 10cm. And you can connect it to a GTA04 on the OTG host port to use the GTA04 as the audio/voice frontend. This will be good enough for the firsts 2-5 years until everything is stable enough to integrate it into a handset.

> community of developers, who could order GTA04A5 boards. 
> Even the separate modem board needs not to be produced before there's any real interest for it. But the GTA04A5 board already needs to be prepared for it, because any later redesign costs much more money and would once more require a new production cycle, what is a really unrealistic scenario. 

Yes, I really appreciate your fresh ideas! And maybe it triggers someone else to new ideas. This is what I would like to ask our community for: new and fresh ideas. And someone who makes them real. We (GD) can only provide new hardware by glueing standard components together but developing new components is beyond our capabilities.


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