Hi,
I have also aquired a SM5100B-D and Shield. I started playing with this module, this morning.
I am new at this ARDUINO environment myself, but I do understand GSM, GPRS, UMTS and WIMAX.
I cannot tell you why, just yet, but I found that if I use a 32K sim card instead of a 64K sim card, all works properly. I have tested the 64k sim in other modules and it works fine.
...Hmmm STANDARDS - maybe, where are they?
I have also not gone through all the literature, but I don't see any explicit exclusions on 64K sim cards. If anyone knows of these; please let me know. :-/
I will write and test more 'sketches'.
Kind regards
MiloSA