Data types: Explanation please!

[jsp91470]

Will someone kindly explain to me, in plain English, the difference between the different types of data services available on the Athena and other 3G devices?

Here's what I know now:The basic voice/data protocol when not in a 3G coverage area is GSM. Since I use AT&T, the 2G (or 2.5G) data service is EDGE. When in the most rural of areas, I'm using simple GPRS for data service, represented by a G on the status bar. When EDGE is available, the G changes to an E.

So far, so good.

Where I'm getting confused is when I enter a 3G service area. It seems that there are two levels of 3G: UMTS (represented by 3G on the status bar) and HSDPA (represented by an H). Also, when in a 3G area, the phone application (and the Wireless Today plugin if it's enabled) show "AT&T UMTS." Now, as I understood it, UMTS is an entire cellular protocol, designed to succeed GSM, and not a data service specifically. HSDPA is the data service.

So, what is the practical difference between a "3G" on the status bar and an "H" on the status bar?

Can someone in the know please sort this out for me?

Thanks.

[raskell]

In simple English the '3G' symbol shows when we are in a UMTS active area. It will show the large "3G" connected to the small "3G" when attached to the UMTS data network but not downloading/uploading anything.

If you then open an application (like Outlook and hit send/receive) the ["3G" 's] both change to ["H" 's] as the HSDPA compression kicks in. This is, of course, depending on having the HSDPA active.

Once the data exchange has ended, it returns to ["3G" 's] to show that we are still in a high speed data 'available' area. If we leave the "3G" area, we get handed of to the "E" 's for the Edge network. If we leave the Edge area, we get downgraded again to ["G" 's] for the GPRS. As you have correctly noted, it's all about speed.

You should only see the ["H" 's] on for an extended time if you are downloading a large file or perhaps streaming media to your device. The "H" shows that the compression algorithm is active, otherwise, the 3G shows when the service is available, but idle.

You may see a single '3G' meaning you are in a UMTS active area but not connected. You should never see a single "H", only a double "H" during a "3G" connected session. I have tested this by turning off HSDPA and the double "3G" remains during downlink, meaning the data is still at a higer speed than Edge, but not using the HSDPA compression. Hope this answers your question.

[mackaby007]

In simple English the '3G' symbol shows when we are in a UMTS active area. It will show the large "3G" connected to the small "3G" when attached to the UMTS data network but not downloading/uploading anything.

If you then open an application (like Outlook and hit send/receive) the ["3G" 's] both change to ["H" 's] as the HSDPA compression kicks in. This is, of course, depending on having the HSDPA active.

Once the data exchange has ended, it returns to ["3G" 's] to show that we are still in a high speed data 'available' area. If we leave the "3G" area, we get handed of to the "E" 's for the Edge network. If we leave the Edge area, we get downgraded again to ["G" 's] for the GPRS. As you have correctly noted, it's all about speed.

You should only see the ["H" 's] on for an extended time if you are downloading a large file or perhaps streaming media to your device. The "H" shows that the compression algorithm is active, otherwise, the 3G shows when the service is available, but idle.

You may see a single '3G' meaning you are in a UMTS active area but not connected. You should never see a single "H", only a double "H" during a "3G" connected session. I have tested this by turning off HSDPA and the double "3G" remains during downlink, meaning the data is still at a higer speed than Edge, but not using the HSDPA compression. Hope this answers your question.

Excellent explanation. Thanks. Not that I needed it, but many noobs to 3G based devices might.

[raskell]

Thanks for your positive comments, mackaby007 :)