4 Ports GSM 1900mhz Fwt

We are offering 4 ports gsm 1900mhz fwt
description of function
1) standard rj-11 of fxo/fxs to telephone or voip gateway & pabx & pstn
2) dtmf detector in rj-11
3) precise reverse polarity
4) caller id (dtmf,one ring) to telephone or voip gateway & pabx
5) single-handed power switch
6) led indicating hook on/off,talking,signal intensity,power on/off
7) strong signals with high gain antenna
8) add prefixed ip number to dail
9) second dial tone
10)base station rotation
optional function:
bar incoming calls
lock sim card
lock mobile service provider
connect to voip gateway for voip termination
connect to pbx system
connect to public-phone system.