... or 16 KHz pulse signal 3)support GPRS 4 line Wireless Terminal Unique Functions1,GSM cellular network outgoing. ... Support secondary dial.5,Lock card, lock terminal.6,Send polarity reversal signal for billing meter ... meter while connection is also compatible.8,Support GPRS . (Optional)9,Rechargeable battery, keep conversation ... Insertion loss: ≤0.5dB 4 line Wireless Terminal/Fixed wireless terminal