VoIP with DrayTek vigor IP PBX 2820 & Linksys SPA941

Running a small business? Fed up of the limitations and cost of a fixed landline or ISDN 30 phone system?  Moving to a VoIP (Voice Over IP) system may seem daunting but is actually fairly simple.

In addition to your existing Internet connection you will need a SIP (Session Initiation Protocol) trunk, we’ve always used OrbTalk.  Once you have signed up they will send you the connection details you need to use when setting up the DrayTek vigor IP PBX 2820.

DrayTek vigor IP PBX 2820

The DrayTek vigor IP PBX 2820 modem router is an all in one ADSL modem, small business router and IP PBX all in one.  I was very impressed with the number of features this device has, including:

  • Dual WAN support (1x ADSL modem + 1 External WAN port)
  • 4 port switch (1x 1000Mb, 3x100Mb)
  • USB port for printer sharing or backup WAN via 3G dongle
  • PSTN phone line support
  • ISDN support

The ability to use dual WAN is great, we have a DSL connection for our main access but also a regular copper landline (for backup voice calls) and a failover 2mb ADSL connection.  The single Gigabit port is great to allow the connection of a server machine or in our case connection to our Gigabit switch.

Linksys SPA941

The SPA941 is actually a Cisco phone branded under Linksys.  According to Cisco it is also an end-of-line model even though availability online seems good at the end of 2010.

It’s a great IP phone, supporting 4 lines and a web interface for configuration.  There are also a nice set of hot keys on the phone for managing calls, putting people on hold and transferring calls between handsets.  The phone also supports direct connection to a SIP trunk so can be used at home if you don’t need PBX functionality.  It’s also very handy for testing your newly activated SIP trunk before configuring the PBX.

Testing the SIP trunk directly on the Linksys SPA941

To test out your new SIP trunk you can put the values directly into the SPA941.  The picture below shows the phones internal web config section, key fields have been highlighted.

SPA941 direct SIP connection

Let the phone reboot and the display should light up and allow you to make a test call to your mobile to confirm all is working.

Configuring the DrayTek vigor IP PBX 2820

The DrayTek actually has a pretty good IPPBX Wizard accessible from the routers web interface.  If you just want to cover the basics of getting VoIP calls setup I’ve outlined the key areas below.  I have assumed you can get yourself an active Internet connection setup first.

[IP PBX] -> [Line Setting] -> [SIP Trunk] to setup your SIP Trunk

Vigor2820 SIP Trunk Setup

[Sip Local Port] and [Proxy Port] are standard for most providers but check with yours.  [Profile Name] and [Display Name] are simply labels.  You should be able to fill in the rest of the details from your provider.

The last two fields we have setup define call handling.  All incoming calls are sent to extension 101 (reception) during office hours and outside office hours all the phones in the main office group will ring. (Groups are trivial to setup, I’m sure you can manage them later)

[IP PBX] -> [Extension]

Now you’ve setup the main SIP trunk you need to add one handset, in our case reception on extension 101

Vigor 2820 Extension Profile

As you can see its pretty self explanatory what needs filling out here, make sure you remember the password you set for the handset as you will need it when you register the handset with the PBX later.

Note: It may be better for a reception phone to forward to a different internal extension if busy rather than go to voicemail but you can choose settings suitable for your environment.

[IP PBX] -> [Dial Plan] -> [Digit Map]

Press 9 for an outside line?  This is where you set it up.

Important: If you do not enter a Dial Plan you won’t be able to make any external calls as the system does not know where to route external numbers.

Vigor2820 DialPlan Setup

The prefix number must be the first number entered and maps the call to the route specified, in this case dialling 9 first routes to VoIP1 (I’ve no idea why this isn’t named  “IP Provider” as we setup in our SIP Trunk?)

The Mode, strip, means that the first occurrence of the number 9 dialled will be removed, leaving the SIP Trunk provider to route the correct number.

Register SPA941 with the DrayTek vigor IP PBX 2820

Log into the web config page of the handset you want to be extension 101 and select Ext1 tab. Where before we entered the raw information from our SIP Trunk provider, this time we enter the details of the local LAN address of the PBX in the [Proxy:] field.  For the [User ID:] enter the extension you setup in [IP PBX] -> [Extension] and enter the [Password:] you chose too.  OK the changes and this should register the phone with the PBX.

Register the SPA941 phone with the PBX

To check everything is working OK go back to the router / PBX web config and check [IP PBX] -> [PBX Status] -> [Extension Monitor]

Vigor2820 PBX Status

Here you can see we have registered three handsets with the PBX that are active and online.

From here you can add more handsets as extensions and create groups for departments.  There are a lot features on this IP PBX and even more on the router so head over to the DrayTek site for the full documentation.

6 thoughts on “VoIP with DrayTek vigor IP PBX 2820 & Linksys SPA941

  1. very helpfull – Thank you

    what about remote IP Phones configuration ?
    Do we have to modify the firewall rules or modify anything on the ippbx ?


    1. Hi,

      I’m sorry we have never connected remote IP phones from outside the local network, I should imagine that you need to open the RTP ports, but as these are dynamic you would have to specify the whole range.

      Also it depends entirely on what codec and protocol you are running to determine the ports to be opened, all I can suggest is searching for the ports you need for your protocols.


  2. As I know, you have to forward port 5060 to the IPPBX 2820. In my care, I forward the port 5060 to

    Stupid, isn’t it?

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