Question about smart phone sim cards

I recently upgraded to an AT&T smart phone from a "regular" phone, and
AT&T provided a new sim card.... so I know it's somehow different from
the sim card I used for several previous phones.

But I opted for the 3 GB/mo data plan instead of the more expensive
$50/mo plan, which would have given me tethering capability of my
phone to my laptop. Now the question... is it possible to use the sim
card from that new phone in an AT&T USB modem that I used to use with
the computer (but have since cancelled the service)?

And a second question,,, can I get in trouble if I just remove the sim
card and try it in the modem?

In article <rc7o08l6mu4i6o59mgc51604mdg1gtj5g6@4ax.com>,
Charlie <invalid@invalid.com> wrote:
>I recently upgraded to an AT&T smart phone from a "regular" phone, and
>AT&T provided a new sim card.... so I know it's somehow different from
>the sim card I used for several previous phones.

Maybe your old SIM card did not support the authentication protocol used
on 3G or 4G networks.

>But I opted for the 3 GB/mo data plan instead of the more expensive
>$50/mo plan, which would have given me tethering capability of my
>phone to my laptop. Now the question... is it possible to use the sim
>card from that new phone in an AT&T USB modem that I used to use with
>the computer (but have since cancelled the service)?
>
>And a second question,,, can I get in trouble if I just remove the sim
>card and try it in the modem?

It would probably work, but AT&T periodically does IMEI scans to check
what types of devices are used on their accounts. If you're caught using
something that requires a different data plan, you could receive a warning
.... or be "automagically" switched to a plan you didn't sign up for.

On Sun, 22 Jul 2012 18:41:40 +0000 (UTC), retsuhcs@xinap.moc (Mike S.)
wrote:

>
>In article <rc7o08l6mu4i6o59mgc51604mdg1gtj5g6@4ax.com>,
>Charlie <invalid@invalid.com> wrote:
>>I recently upgraded to an AT&T smart phone from a "regular" phone, and
>>AT&T provided a new sim card.... so I know it's somehow different from
>>the sim card I used for several previous phones.
>
>Maybe your old SIM card did not support the authentication protocol used
> on 3G or 4G networks.
>
>>But I opted for the 3 GB/mo data plan instead of the more expensive
>>$50/mo plan, which would have given me tethering capability of my
>>phone to my laptop. Now the question... is it possible to use the sim
>>card from that new phone in an AT&T USB modem that I used to use with
>>the computer (but have since cancelled the service)?
>>
>>And a second question,,, can I get in trouble if I just remove the sim
>>card and try it in the modem?
>
>It would probably work, but AT&T periodically does IMEI scans to check
>what types of devices are used on their accounts. If you're caught using
>something that requires a different data plan, you could receive a warning
>... or be "automagically" switched to a plan you didn't sign up for.
>
>

Hmmmm. Thanks for the answers... maybe it just isn't worth trying it
out. If I get in a situation where I "need" access I'll probably give
it a shot, otherwise, I'll leave it as-is.

On Mon, 23 Jul 2012 05:03:54 -0700, Evan Platt
<evan@theobvious.espphotography.com.invalid> wrote:

>On Sun, 22 Jul 2012 10:41:27 -0500, Charlie <invalid@invalid.com>
>wrote:
>
>>I recently upgraded to an AT&T smart phone from a "regular" phone, and
>>AT&T provided a new sim card.... so I know it's somehow different from
>>the sim card I used for several previous phones.
>>
>>But I opted for the 3 GB/mo data plan instead of the more expensive
>>$50/mo plan, which would have given me tethering capability of my
>>phone to my laptop. Now the question... is it possible to use the sim
>>card from that new phone in an AT&T USB modem that I used to use with
>>the computer (but have since cancelled the service)?
>>
>>And a second question,,, can I get in trouble if I just remove the sim
>>card and try it in the modem?
>
>It very likely won't work. Data from a modem is different, and they
>know that. It MAY work for part of a day, then stop working.

I guess a reason I thought it might work is because back when I had
the modem activated, I sometimes got messages and information from
AT&T that "sounded" like they thought I had a phone, ie like they
thought I had voice capability.

What the heck, if I get bored I just might try it and see. As it is,
I've now figured I can tether the phone using a USB cable and PDAnet,
so there's really no longer an incentive to actually use the sim card
in the modem.