The type of calls supported by the SPA-3000 can be described in terms of the originating, intermediate, and terminating interfaces involved:
1. FXS to VoIP1
2. VoIP1 to FXS
3. FXO to VoIP2
4. VoIP2 to FXO
5. VoIP1 to FXO
6. FXO to VoIP2 to VoIP1 to FXS
7. FXS to VoIP1 to VoIP2 to FXO
#1 and #2 are conventional VoIP calls.
#3 lets a PSTN caller hop-on to use VoIP service.
#4 lets a VoIP caller hop-off to use PSTN service.
#5 is similar to #4 except the caller establishes the VoIP call leg by calling the VoIP1 interface instead of the VoIP2 interface.
#6 allows the PSTN call to ring the FXS port phone; we called this “ringing thru”.
#7 allows you to call the PSTN from the phone.
Notes:
VoIP1-to-VoIP2 and VoIP2-to-VoIP1 are internal SIP calls. Signaling and media packets are sent to the loop back address 127.0.0.1. Hence call types #6 and #7 are possible even if the Ethernet port is not connected.作者: 角色 時間: 2011-7-3 00:10