Integrating a Legacy PABX with 3cx

[kingdavid]

Hi Guys,

A client of ours operates a large company. It happens that they wish to migrate to an IP PBX, however the brass wish to see the efficacy of an IP PBX in operation. The following scenario has occurred; They have a legacy PBX at one of their locations and it is connected to the rest of their network. They wish to link 12 extensions (lines) on this PBX to a new site which will be used to test an IP PBX. What they want is for the 12 extensions (i.e. lines) on the present site to function as extensions (terminals)at the remote location.

The scenario we have in mind is to connect the 12 lines at the PBX to a 12 port FXO gateway which is connected to their LAN. We'll then setup a 3cx PBX at the remote site and create 12 extensions on it. The we'll map each of these lines on the FXO to correspond to an extension on the 3cx. We will create an outbound rule with a suffix which corresponds to their existing dialing rules (5 digits) for the 3cx 9which will have 3 digit extensions). What w wish to achieve is to create a separate PBX/Intercom network at the remote site in which each of the extensions can communicate locally, ca communicate with the legacy PBX by dialing with the 2 digit prefix, and can be communicated with by the legacy PBX by simply dialing the line which corresponds to the premapped extension on the FXO.

I hope this is clear.

What we need is confirmation that this can work, or modifications to achieve seamless communication between the remote site and the legacy PBX.

Many Thanks

Dos

 

[leejor]

It sounds to me like it will work, you're using the 3Cx to extend the extensions oner the internet to a remote location. each FXO ports being an extension on the existing board. You'll be able to test it out with the free version but it only allows 4 concurrent calls. Also keep in mind that 3CX has it's own Voicemail system, the existing PBX system voicemail should be disabled on the extensions you are going to use as there is no way for the legacy board to notify the voip phones that there is a message.

 

[kingdavid]

Dear Leejor,

Thanks a lot, i'm attaching an illustration to show what we wish to achieve, it is scenario 2, this is the link;
http://www.ziddu.com/download/5436487/GXW41xx_userManual.pdf.html. if you can reply today that will be great as we need to implement this solution by saturday. i need specifics of how to implement this solution. thanks once again

Dos

 

[leejor]

Sorry about the delay, I'm on holiday in the UK at the moment and don't spend a great deal of time on the laptop.

The gateways lines will each have to be set up as individual trunks, one per extension number from the existing PBX. You want the sets working at a remote location so you will have to set those lines to register to either a fixed public IP of the 3CX location or use a DDNS service (if you have an IP that will change), many routers have that feature built in. you will also have to forward the required ports to the IP of the 3CX. If you have the sets then, they, and the 3CX should be set up fairly quickly. you'll have to build incoming and outgoing rules so that each phone goes out only on it's own gateway and calls coming in on those gateways ONLY go through to the assigned set. I'm going to say that it will probably require some testing and tweaking. Concentrate on getting calls between two sets first, then add the gateway(s), one at first and get just one working . Once that works you will then have a basic template to set up the rest of them.

 

[bblokey]

I am trying to do the same thing...

1. Did you get this to work?
2. Can I look at your diagram of your setup?
3. Are your current legacy PBX lines digital?
4. What hardware did you use to inter-connected your PBX and 3CX? (actual brand and model)

Thanks,
Agustin

 

[leejor]

Don't forget that you numbering plan (for the extensions) is going to be a bit different from the legacy PBX. For example if the extension numbering on the legacy PBX is 201,202,203....299. you don't want to give the 3CX extensions the same range. you could give them 301, 302....etc. You juts don't want a conflict. When a legacy caller dials, for example 201, it will ring the 3cx extension, which is really 301. You wouldn't have to dial the 3xx numbers because you are letting the legacy PBX do the switching, but you could from another 3CX phone.

 

[kingdavid]

Dear Leejor,

Thanks Man, i really appreciate your input. This is exactly what we had in mind. I'll let you know how it goes as soon as we set up!

Cheers