Hi Saeedas,
You can find the hardware reference documents of the EM series from the below link 
http://developer.sierrawireless.com/Resources.aspx#&&filter=Devices-eq-(25311A60-7CCB-42A5-B1F3-92F9B1655895)!(3C4A040A-E262-4503-BC6A-0B7909D62FF3)!(749948D6-15E5-42BC-A176-71D641DC81DB)
Thanks,
Rex