... : GSM(A) ,GSM (B) and GSM(C),Conveniently choose GSM(A),GSM(B) ,GSM(C) or PSTN Auto-select Low cost route. TM2000D-3 PSTN /GSM Fixed Wireless Terminal (GSM ... + 1 PSTN)I. FeaturesSupport 3 SIM Cards : GSM(A) ,GSM (B) and GSM(C),Conveniently choose GSM(A),GSM(B) ,GSM(C) or PSTNAuto-select Low cost route ...