... GPRS Module (GSM 900/GSM 1800) with R232 interface on CMOS level and AT command set.GPRS wireless date ... Internal SIM card reader and option on external SIM card reader Full RS232 on CMOS level with flow control ( ... CTS,RTS,CTS,DIR,DSR,DCD,RI) High performance on low price Interfaces:Power supply nominal: 3.8v ... audio for microphone, speaker and hands free set RS232 on CMOS 2.8v (One RS232(2.8v) with ...