© 2003 - 2005 Sipura Technology, Inc
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This feature allows a PSTN caller to ring Line 1. When the PSTN line rings, the FXO Line makes a
local VoIP call to Line 1. If Line 1 is busy, stops… After a given number of rings, the VoIP gateway
picks up the call.
4.9. Symmetric
RTP
Symmetric RTP is to send audio RTP to the source IP and port of the inbound RTP packets. This will
facilitate NAT traversal.
Parameter Group
Description
Range
Symmetric RTP
Line 1
Enable symmetric RTP operation. If enabled, SPA
sends RTP packets to the source address of the last
received valid inbound RTP packet. If disabled, SPA
sends RTP to the destination as indicated in the
inbound SDP. Default is yes.
Bool
Symmetric RTP
FXO
Same as above. Default is yes
Bool
4.10. Call Progress Tones
4.10.1. VoIP PIN Tone
This tone is played to prompt a VoIP caller to enter a PIN number.
4.10.2. PSTN PIN Tone
This tone is played to prompt a PSTN caller to enter a PIN number.
4.10.3. Outside Dial Tone
During 2-stage PSTN-Gateway dialing and a non-trivial dial plan is assigned, the SPA will collect
digits from the VoIP caller and process the number by the dial plan. The SPA plays the “Outside Dial
Tone” to prompt the VoIP caller to enter the PSTN number. This tone should be specified to sound
different from the PSTN dial tone.
4.11. Call
Scenarios
This section describes some typical scenarios where the SPA-3000 can be applied. Please read
these scenarios sequentially as some special terms are introduced in the first few sections and re-
used in later sections without re-explanation.
4.11.1. PSTN to VoIP Call w/o Ring-Thru
PSTN caller calls the PSTN line connected to the FXO port. Ring-Thru is disabled. After it rings for a
delay equals to the value in <PSTN Answer Delay>, the VoIP gateway answers the call and prompts
the PSTN caller to enter a PIN number (if PIN authentication is enabled). After a valid PIN entered, a
regular dial plan is played to prompt the PSTN caller to dial the VoIP number. A dial plan is selected
according to the PIN number entered by the caller. If authentication is disabled, the default PSTN dial
plan is used. Note than the dial plan choice cannot be 0 for a PSTN caller.
Note: A <PSTN Access List> in terms of Caller ID (ANI) patterns can be configured into the SPA-
3000 to automatically grant access to the PSTN caller without entering the PIN. In this case, the
default PSTN dial plan will be used also. (PSTN Access List feature is not available at the moment)