Two phones, One Extension

Discussion in '3CX Phone System - General' started by nthomthom, Mar 30, 2012.

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  1. nthomthom

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    I have two linksys SPA phones configured on an external site from server. Everything seems to work but I want both phones to have the same extension number. When I do this there are some problems such as one sided audio (at random). Is there a proper way to configure the phones so that they share the extension number, or would it be easier to just give them a separate ext and group them together?
     
  2. leejor

    leejor Well-Known Member

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    I'm assuming that both sets are behind the same remote router?
    First, be sure that you have given each set a different port number, 5060 & 5061. You may also want to try changing the PBX delivers audio option in the 3CX extension settings.
     
  3. albertc

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    Correct me if I am wrong. But my understanding about sip is unless the server is listening to both 5060-5061 for sip traffic, otherwise, the phone that set the SIP reg port to 5061 will not able to register with the server simply because the server is not listening to that port. It's just like having two computers on the same local network trying to access the same web site "web server", you dont need to tell one computer to use port 80 and another to use port 81 just so both computers can interact with the web server at the same time.

    Whenever there is a one way audio issue, it is almost always the problem at the firewall(s) where RTP 9000-90XX is not being translate/forward correctly. First thing to check is to make sure your 3cx server has passed all the firewall test without any translation using the firewall checker. That is important for a smooth and reliable remote extension setup without using SIP proxy Manager. Once you are able to make one of the two phone works perfectly, you can just copy the setting of that phone to the 2nd set and it should work just fine. When you get a call on that extension, both phones should ring at the same time and you can answer either one of them (the other phone will show a miss call). I just tested that myself here at a remote location using two softphones with the exact same setting and exact same extension and it work just fine.
     
  4. leejor

    leejor Well-Known Member

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    The port I'm referring to is not the port 5060 that the devices will be registering with (at the 3CX PBX end). I'm referring to the port that is assigned to each SIP device.

    In most cases (for a single line device), that particular port defaults to 5060. But,if you are using more than one device behind a router (shared public IP), then each will be required to have a unique port number or 3CX will not be able to contact more than one device. From outside the local LAN, each device is identified by...(public IP + port number)

    If, for example, you look at a multi line ATA, the SPA-2102...there are two lines within the device, sharing a common IP. Line one defaults to port 5060, line two is 5061. The same principle applies to remote devices behind a router unless you are making use of the 3CX Proxy Manager.
     
  5. albertc

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    The port you define on your sip device is which port to send the sip signal to. I have a cisco pap2 ATA (very similar to the spa-2102) and it has two lines sharing a common IP. I have both line setup exactly the same using port 5060 and connected to the exact same 3CX server with the exact same public ip address offsite. The only different is line one is setup to use with ext 102 and line two setup to use ext 200. It works just fine. I did setup line one and line two using the same extension in the past and i did not have any trouble making incoming or outgoing call on both line. When a call comes in, both lines will ring at the same time and i can pick up and use either one of them. So, using different port is really not necessary in this case if you need to setup two phones with the same extension.
     
  6. leejor

    leejor Well-Known Member

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    Yes, that's one of them, that's the port you register to (the one 3CX is "listening on"). You also have a port assigned to each SIP device within the ATA or SIP hone that you are using. It's the port that the device tells 3CX how to reach it.

    The normal set-up for SIP devices that "contain" more than one "line", is to assign each a unique port number. That is the way they generally come from the factory. The defaults for the PAP2T and SPA-2102, are line one as port 5060 and line two as 5061, just as the SPA-3102 has Line one as 5060 and the PSTN line as 5061.
    To change them both to the same port number, when located behind a router, registering to the same SIP server, is asking for problems.
     
  7. albertc

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    Have this setup for almost half a year already. Never have a single issue. Maybe i m just lucky. (crossing my fingers) ;)
     
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