convert pstn to voip then back from voip to pstn

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May 17th, 2010
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I ordered a  spa-3201, pap2t and spa2102 for a project hoping it would work and having configuration problems.

I have a main building with a PBX and 6 phone lines. I have a wireless bridge to another building about 2 blocks away which is currently connecting network and running at 1MB up and down speed. I wanted to run voip through this to put 1 phone at remote building and to tie into pbx. Is this possible with equipment I purchased and/ or has any body done this?

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Howard Wittenberg Mon, 05/17/2010 - 19:33
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You can interface an analog PBX with the SPA3102 and bridge a call to a distant voip ata adapter.  The distant adapter could be either the pap2T or the SPA2102 that you said that you purchased.

One setting that is often overlooked in configuring for this application is the SPA3102 "Line In Use Voltage" on the FXO (PSTN Line) port.  Analog PBXes usually operate with a lower voltage level than a standard PSTN line and the default setting for "Line-In-Use Voltage" needs to be adjusted to a voltage setting about half way between the on-hook and off-hook voltage level of the PBX analog interface.  You can read the voltage level at any point in time on the SPA3102 INFO Tab.  If the setting is not correct the SPA3102 will not take the SPA3102 FXO port off hook to place a call because it believes the line to already be in use.

todd.bourne Wed, 05/19/2010 - 14:04
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Right now I have connected spa3102 line port to pstn and the ethernet port to lan with static ip. On the remote end I have PAP2t ethernet connected to lan static ip same network and line 1 to analog phone. It is configured and works to get dial tone and dial out from pap2t through network to spa3102 and out line port. Now I need to be able to get pap2t to ring and or accept incoming calls. Can you help? Then I will connect to pbx.

Howard Wittenberg Wed, 05/19/2010 - 18:21
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Todd, you've got half the battle conquered. 

For the incoming pstn line call to ring the distant PAP2T you would have the following configured:

On the SPA3102 PSTN Line Tab:

PSTN-To-VoIP Gateway Enable: yes

PSTN Caller Auth Method: none

PSTN Ring Thru Line 1: probably no unless you want the phone locally attached to the SPA3102 to ring on an incoming pstn line call.

PSTN CID for VoIP CID: yes

PSTN Caller Default DP: 2

Off Hook While Calling VoIP: no

Dial Plan 2: (S0<:[email protected]_address:port>)

where userid is any userid you have setup on the PAP2T Line configuration, ip_address is the PAP2T ip address, port is the Sip Port configured on the PAP2T Line configuration.

Make Call Without Reg: Yes

PSTN Answer Delay: 3 (long enough to receive the incoming caller id).  Make setting longer if you wish the phone locally attached to the SPA3102 to ring on an incoming pstn line call.

On the SPA3102 Line Tab:

Enable IP Dialing: Yes

On the PAP2T Line Tab Configuration:

Ans Call Without Reg: Yes

valerio martellotta Mon, 12/01/2014 - 23:37
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hi, this configuration on my system: SPA3102 and PAP2T works at half way, I mean: I can answer call from the PAP2T but I cannot call. When I dial number, I got always busy tone.

what's wrong?

I've set "make call without reg": yes on the both of devices



Dan Lukes Tue, 12/02/2014 - 00:22
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Don't post your question into unrelated thread. Create the new one. Thank you.

todd.bourne Wed, 05/19/2010 - 19:04
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This worked. Thank You.

Now I just have to hook up 3102 fxs or line port to pbx and configure to dial 9 to get outside line or just dial an extensionc from the pap2t


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