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Title: Circuit Switched Data over UMTS - have you done this on the Three network? Post by: A1ia5 on November 06, 2008, 12:29:55 AM Has anyone done Circuit Switched Data (CSD) over the Three UMTS (3G) network in the UK ?
If you have then... * What was the data throughput like * Were you charged or did it come from your inclusive voice minutes * Any other comments you like to make I understand that theoretically a speed of 64kbps is the maximum, but, as always, this is rarely the case in practise. Interestingly, this is significantly higher than CSD via GSM, which is 9.6Kbps. Cheers Title: Re: Circuit Switched Data over UMTS - have you done this on the Three network? Post by: A1ia5 on November 06, 2008, 02:29:32 AM Research seems to indicate it is unlikely to be possible to do it...
http://www.securegsm.com/pages.php?pageid=85 Above is cool app too, as you should know that standard GSM is not secure ! However, changing the phone to use GSM may enable this, but at the much reduced data rate of 9.6K. I recall reading some months ago that CSD via UMTS was enabled on the Three network, but they caught on and stopped it. I need to do some tests and find out. Again it seems that O2 allow CSD via GSM from inclusive mins - I know as I have done this. I didn't use the WAP service on the phone as it is cr4p. It was just simply as a modem hooked up to a host pc. This kind of comes back to some other research I have conducted on tunneling data via Skype. I wonder if it is possible to disguise a data call as a voice call and therefore use inclusive mins. I know the answer already - yes - but don't know how to do it - and the cincher is what would the date rate be. Again I think the answer is no where near as much as a genuine CSD via UMTS call. Plus there is a greater overhead on the host PC to work with raw audio from the phone and push audio back out through the phone. Ha - it's never easy - but thats the fun of the journey ! Title: Re: Circuit Switched Data over UMTS - have you done this on the Three network? Post by: A1ia5 on November 06, 2008, 02:55:06 AM Thinking about this a bit more - it may well be a lot easier than i first thought. Given three do not allow CSD via UMTS, all I need to do is use some old data protocol, say such as Kermit or even one of my old favorites (a)X25. Then to get the audio to and from the phone this should be possible from the headset or I could go fancy and do some special bluetooth link, as that of course exposes the ear and mic audio in a better digital format (note here - this is how Asterix - the VoIP PABX - manages attached mobile phones).
Key is getting the highest data throughput with the service provider regarding the call as a voice call. There are actually many protocols to choose from. From my radio experience I have sent and decoded computer generated morse, AMTOR, RTTY and more. AMTOR (Amateur Telegraph over Radio) is particularly good as it has error correction in-built and has a lovely sound ! Further, if I could have multiple calls on the one phone or have several phones attached I can linearly increase the bandwidth between the two points. Title: Re: Circuit Switched Data over UMTS - have you done this on the Three network? Post by: andy on November 06, 2008, 03:09:19 AM Key is getting the highest data throughput with the service provider regarding the call as a voice call. Further, if I could have multiple calls on the one phone or have several phones attached I can linearly increase the bandwidth between the two points. I hope this won't sound insulting, but I'm getting the impression that your imagination is running away with you on some of these topics at the moment. It's not a bad thing to do occasionally, but ... I can't see the point of this either, as I think it highly improbable that you can send data as a voice call and expect it to go any faster than the GSM codec, which speed you seem to have already mentioned. Use HSDPA data, which is hundreds of times faster |