List of WWAN card models for Toughbooks:
MC7750 (xxV4GLTEFU)– Sierra Wireless branded Airprime - 4G LTE Verizon Specific card (Win 7 Only) – Not licensed for Win8.
MC7725 (xxA4GLTEFU) – Sierra Wireless branded Airprime - 4G LTE AT&T specific card (Win 7 Only) – Not licensed for Win8.
MC8355 GOBI 3000 (xxGOBI3FU) – Sierra Wireless/Qualcomm dual branded – “Multi-carrier” 3G card – Sprint EVDO revA CDMA, Verizon EVDO revA CMDA and AT&T 7.2M HSPA+ GSM.
MC7355 GOBI 5000 (xxGOBI5000FU) – Sierra Wireless/Qualcomm dual branded - 4G LTE multi-carrier card – Licensed to work with Windows 8/8.1.
KEY: xx = 19,31,52, 53, C1, C2 or whatever Toughbook model you’re putting it into.
If anyone has any additions to make please post them so I can update the 1st post here.
The current 4g lte modem for At&t is the MC7700 not 7725. I'm assuming that's a typo, i tried to lookup and didn't find anything