Call failures with SQN-100-5 (T-Mobile) on AT&T

Question

I bought a factory-sealed, T-Mobile-branded Q10 on eBay a couple of months ago. At the time I was with T-Mobile, no problems with making or receiving calls.  I wanted to switch to AT&T for the better coverage, so I got the unlock code from T-Mobile.  Now when I try to place calls, half the time I will get a call failure message.  Sometimes it takes 3 or 4 attempts to make a successful call. And a lot of calls I receive will go directly to voicemail. I spoke with someone in AT&T support and she said that, even though the phone was unlocked, because it was a -5 model instead of a -1, that I would continue to have this problem and, sorry, there was nothing they could do about it.
I'm no expert concerning cell radios & bands, but I see on the Q10 Wikipedia page that the only difference between the two models is with 3G.  AT&T is tri-band, while T-Mobile is quad-band. T-Mobile also uses 1700  which AT&T doesn't.
Is this the reason for the call failures?  If not, is it worth pursusing this with maybe Level 2 or Blackberry Support at AT&T to see if anything can be done on their end?

Answer 1

Hello,
There are multiple sub-models of each BB10 device, each supporting specific radio frequencies, bands, and technologies. The challenge in the USA is that we allowed our cellular industry to grow relatively unregulated all by itself, which has resulted in great variability between the carriers in this regard. And, to make a device actually able to handle ALL of those would mean that the device is so physically large (multiple internal antennas) as to be unacceptable to the end user. Hence, the multiple different sub-models of devices.
What you were told is indeed the case...your specific sub-model of Q10 is only partially compatible with AT&T's network, and you will indeed continue to have challenges. Unfortunately, there is nothing anyone can do to alter the (in)compatibility between your -5 device and AT&T's network.
If you truly want the best compatibility, you need to obtain a device that is fully compatible with AT&T's network. And, you of course can then sell your -5 to someone on TMO who desires it.
Good luck!
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