... -reverse,12 or 16 KHz pulse signal 3)support GPRS 4 line Wireless Terminal Unique Functions1,GSM cellular network outgoing.2, ... GSM cellular network incoming.3,DTMF Caller ID.4,Support secondary dial.5,Lock card, lock terminal.6,Send polarity ... pulse for billing meter while connection is also compatible.8,Support GPRS . (Optional)9,Rechargeable battery, keep conversation for at least ...