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Making Analog calls from a Linksys SPA941/942 IP Phones using the Sipura 3000 ATA PDF Print E-mail
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Written by Web Master   
Monday, 30 July 2007
The first thing that might pop into your mind is why would want to do this? As much as we all like VOIP it doesn't work 100% and it lets us down. Most business are not ready to give up their reliable PSTN line(s). And why should they have to if they can enjoy the best of both worlds. They can add VOIP lines for long distance savings and still keep a PSTN line as a backup.

I have been using my Linksys SPA941 phone for almost a year now and I have nothing but great things to say about this phone. It feels solid, sound quality is excellent, and it's very reliable. The Linksys SPA941/942 phones also work great with Asterisk/Trixbox deployments.

Recently one of our clients wanted to implement some redundancy for their virtual PBX setup. I went to talk to them about some options and also configure a Linksys WIP300. The WIP300 quality seems to have improved with the most recent firmware in comparison to the last WIP300 I configured. Please don't buy a WIP300, the battery life is terrible!

 

The original idea the client had was for the SPA3000 to call forward his current PSTN number to his new VOIP number. If for some reason SPA3000 couldn't forward the PSTN calls it would start forwarding them to either a cell phone number or to voice mail. This all sounded great to the client but I have also been using the SPA3000 and in order to do what he wanted it would involve more than one PSTN line and more than one SPA3000 without using a VOIP/Internet setup.


Instead I suggested a much simpler solution. Since the client was using AT&T for PSTN I let him know that he can use what is called “Call Forward No Answer” service. This would allow him to forward his current PSTN number to his VOIP number. In case the VOIP service went down the “Call Forward No Answer” service would ring to either to his cell phone or forward the caller to voice mail. He seemed much happier with this solution as it eliminated an additional piece of hardware.


This got me thinking now, if the VOIP service did go down it would be nice if the call forwarding on the PSTN could be deactivated and calls could be answered using one of the office IP phones. I knew about IP dialing but never gave it much thought about using it in this scenario. I looked on the internet to find out if someone had done this. At first I didn't find anything because I was mostly searching for the wrong keywords. I ended up posting what I wanted to do in the Linksys Forums and I quickly got a reply with some helpful information.


I ended up doing some additional searching and I ended up finding the information I really needed on the Sipura site. Sipura is the company that made the SPA3000 before it was acquired by Cisco/Linksys. Reading Sipura's FAQ on the SPA3000 what I wanted to do was called a hotline. And there was some simple examples on how to do what I wanted using two SPA3000 ATA's.


I took the information and made a few changes to implement a hotline using my SPA941 and SPA3000. I configured my Ext2 line on the SPA941 to IP dial the SPA3000 analog line. I also configured the SPA3000 to forward all PSTN calls to the SPA941. I have my Ext1 line configured to use my VOIP account and if that ever goes down I can just hit Ext2 line to dial out using the PSTN line, all this from one IP phone.


I never did hear back from the client if he wanted to implement anything more than the “Call Forward No Answer” service. I did however end up with a nice solution that I can suggest to other Virtual PBX customers.


If you want to implement this solution follow the step by step instructions below.


Note: We are only using the SPA3000 as PSTN gateway in this example. We are not connecting to a VOIP provider.


Our SPA3000 IP address is 192.168.1.100

Out SPA941 IP address is 192.168.1.111


Make sure to replace our example IP addresses to your actual IP address for your devices.

From your web browser go to 192.168.1.100, select advance and admin options. This will expand all the menu options. Select Line 1 tab.

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Set Make Call Without Reg: yes

Ans Call Without Reg: yes

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Set Enable IP Dialing: yes

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Switch to the PSTN Line tab

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Set Make Call Without Reg: yes

Ans Call Without Reg: yes

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Set Dial Plan 2: (S0<:192.168.1.111>)

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Set Ring Thru Line: no

PSTN Caller Default DP: 2

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Set PSTN Answer Delay: 0

(Increase this number to 3 or higher if the CID is not being received to your IP phone)

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Lets now Configure the Linksys SPA941

From your web browser go to 192.168.1.111, select advanced and admin options. This will expand all the menu options. Select Ext 2.

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Set Make Call Without Reg: yes

Ans Call Without Reg: yes

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Set Dial Plan: (S0<:192.168.1.100>)

Enable IP Dialing: yes
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If you have made all the changes above to your SPA941 and SPA3000 you should be able to select Line 2 from your phone and hear a dial tone.



 

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