Well, here's your problem T-Mobile!
After unlocking one of the MDAs using LokiWiz (see our entire pictorial tutorial here), we inserted a prepaid 64K Cingular SIM card and guess what happened?
The MDA no longer had network registration problems or reception weaknesses. In this article, we have two MDAs - one with a new T-Mobile SIM card and one with a new Cingular SIM card - that we put side-by-side to show you the differences between them when operating under T-Mobile and Cingular simultaneously...
Here you see the front and back of the new Cingular SIM. Nothing too exciting here...
Front of SIM:
Back of SIM:
Here we inserted the two carriers' chips into the backs of the MDAs. The one on the left is T-Mobile's and the one on the right is Cingular's. We'll keep this arrangement throughout our testing.
(Click on image to enlarge)
Immediately after turning on both devices simultaneously, the Cingular MDA now has full signal strength while the T-Mobile MDA begins its endless search for its network.
Even in parts of the house where the T-Mobile MDA has no coverage, the Cingular MDA is able to get up to three bars with good voice quality (no chopiness, fades, etc.).
Also, in our past tests where we took the T-Mobile MDA from inside an elevator where all phone signals drop to immediately outside where signal always picks up, the Cingular works as other phones do.
It's our short-term conclusion that the MDA itself operates fine as a phone device. The problem lies within how the firmware in the phone does its thing to register onto the network and the strength of the local towers between the two carriers. Clearly, Cingular's ad campaign of "Raising the bar" is holding up quite true to its claims, while T-Mobile's "Get more" unfortunately applies to all things except strong signals and coverage.
Now to be fair, in Northern California, Cingular/AT&T has always had good signal whereas in T-Mobile's (previously VoiceStream Wireless which never had presence in NorCal) effort to go nationwide, had to rely on agreements with Cingular to share its towers. Thus it may appear as though in certain areas where towers may be more pro-Cingular, T-Mobile devices with issues in its firmware would exhibit confusion as to which tower to register onto and how it does so thereby exhibiting this endless searching problem that's plagued all T-Mobile MDAs. If you go into areas where you previously had solid VoiceStream coverage such as in the East Coast and in the Mid West (?), you may not see the same behaviour.
It should also be noted that we have read claims that Cingular and T-Mobile operate natively on different bands. Cingular operates on 850Mhz while T-Mobile operates on 1900Mhz. I'm no radio expert, but generally speaking, the lower frequencies can travel through brick and stone more easily than with higher frequencies where absoprtion becomes more evident. While both 850Mhz and 1900Mhz are UHF line-of-sight frequencies, the ones lower on the spectrum would be the ones more "building friendly". This may also explain why even other carriers' devices (Nextel, Sprint) always had good reception in my house. We'll be using CellPhoneProfileSwitcher to identify towers and get a bit more scientific later...
And the bottom line is this:
(click on image to enlarge)
The Cingular MDA (right) works while the T-Mobile MDA (left) doesn't.
Here are the videos we shot (available here and on YouTube, GoogleVideo). It had to be split into 3 parts to work with those services. To view the ones on our site, just click the picture:
YouTube Hosted Video
YouTube Hosted Video
YouTube Hosted Video
Posted 06/10/2006 by Administrator | Filed under: MDA / 8125 / 6700
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