Sunday, 3 January 2010

Configuring SPA2102 VoIP ATA with CallCentric

The focus of this article is to illustrate how to configure the Cisco Linksys  SPA2102-NA  with a BYOD (bring your own device) VoIP carrier, such as CallCentric.


To keep things as simple as possible, I will start from the factory default settings and only change configuration settings that are most important to get started connecting to CallCentric on Line-1, which is my primary VoIP carrier I have been using for years.

NOTE:  These instructions only work on UNLOCKED versions of SPA2102-NA.
If you purchased your ATA from an authorized Cisco-Linksys reseller, it will likely be an unlocked -NA version.

My examples are based on SPA2102-NA Firmware Version = 5.2.10 and Hardware Version 1.3.5(a).
My SPA2102-NA is directly connected to my ISP high-speed Modem. (Recommended)

I will be following these basic steps:
  1. Reset SPA2102 to Factory Defaults using its IVR interface
  2. Login to the SPA2102 web-based configuration interface
  3. Configure primary/secondary DNS servers and NTP Time Servers
  4. Set your local Time Zone clock offset
  5. Configure Line-1:  VoIP Proxy, User ID, Password, Codec, Dial-Plan
I recommend using the SPA2102 directly on the output of your Internet Modem.  For best performance and reliability, there should not be any NAT-Routers before the SPA2102.  This also means that your Modem should not have a NAT-Router built into it.  The SPA2102 has its own built-in NAT-Router and Firewall.  So, the rest of your network is protected when connected to the LAN port of the SPA2102.  If you have multiple LAN devices that need to be connected, you can connect your router, or Ethernet Switch,  "after" the SPA2102 through its LAN port.

Reset to Factory Defaults
The reason I am beginning with Reset to Factory Defaults is to ensure that we are on the same page with all the same default settings.  If it works for me, I presume it will work for you too.

To reset to factory defaults requires that I access the SPA2102 IVR system (Interactive Voice Response) using a regular telephone plugged into the Line-1 phone jack (RJ-11 jack).  Then, power up the adapter.  It will only take about 15 seconds to power-up to the "ready" state.
  1. To activate the SPA2102 IVR, lift the phone handset and press the Star key four (4) times (* * * *).
  2. After the IVR voice prompt, enter the Factory Reset code:  73738, followed by the # key (73738#).
  3. The IVR will prompt you to "press 1 to confirm".
  4. As soon as you press "1", the unit will perform the factory reset.
Now that we are at a known default starting point, we can proceed to configure only those settings that are required, or otherwise recommended.

Connect and Login to the SPA2102 Web Based Configuration Interface
Connect your PC to the SPA2102 using its LAN-side gateway:
  1. Connect your PC Ethernet LAN cable directly to the yellow Ethernet LAN port of the SPA2102.
  2. Connect to the SPA2102 web interface by entering its LAN gateway IP address into your Web Browser using the default address of
  3. By default, you will be viewing the SPA2102 "Status" page, in "Basic" view.  By default, there is no password required to connect and login to Basic view.

The screen captures I'm currently posting here are based on firmware version 5.2.10.
In previous articles I posted the procedures for upgrading firmware in the SPA2102-NA and PAP2T-NA VoIP adapters.  It is advisable to always use the latest firmware version available.

To begin configuration of the SPA2102, you need to switch to "Admin" and "Advanced" view. 
By default, the SPA2102 does not require an admin password. 

Now, navigate to the WAN Setup tab. 

Configure Primary/Secondary DNS Servers and NTP Time Servers
DNS servers lookup the IP address of an Internet resource based on domain name to IP address cross referencing. Typically, we configure a VoIP proxy based on its domain name (i.e. ).  DNS servers will redirect your Internet traffic to the appropriate IP address of the VoIP proxy.  The same goes for the NTP (Network Time Protocol) time servers.  Your ATA uses NTP time servers for tagging and maintaining the correct device time.  NTP time servers are listed by domain names.  The DNS servers will direct the NTP requests to the appropriate NTP time server IP addresses.

By default, the SPA2102-NA should retrieve the DNS server info from your Internet Modem DHCP server. However, I prefer to ensure that the DNS servers are hard coded, as well as automatically retrieved via DHCP, to ensure reliability, redundancy, and backup.

In my examples, I have configured my SPA2102-NA Primary and Secondary DNS servers to point to the new Google DNS servers at and  I also use NTP time servers at and  If you have different server preferences, feel free to use them instead of the ones I use.  As well, you can set the DNS Server Order = "Manual, DHCP" to use DHCP DNS servers as backup to your manually set primary/secondary servers.

For now, the default QOS settings should be suitable to begin with.

Click the Submit All Changes button to SAVE your custom settings.

Next, navigate to the Voice and Regional tab page.  Scroll to the bottom of the page.
Set your local Time Zone offset, depending on where you live.

Click the Submit All Changes button to SAVE your custom settings.

Configure Line-1:   VoIP Proxy, User ID, Password, Codec, and Dial-Plan, etc...
Navigate to the Voice and Line-1 tab page.

The Line-1 page is where you will be configuring VoIP service with your primary line (Line-1) and carrier.

While you can configure any SIP based VoIP carrier here, that allows BYOD (bring your own device), I will be using  CallCentric to illustrate the CallCentric "required settings".  If you are configuring with another VoIP carrier, it is essential that you consult their support pages for their specific settings required by that specific service.

The following settings must be set as specified by  CallCentric:
  • NAT Mapping Enable:  No
  • Nat Keep Alive Enable:  No
  • Proxy:
  • Use Outbound Proxy:  Yes
  • Outbound Proxy:
  • Use OB Proxy in Dialog:  Yes
  • Register:  Yes
  • Make Call Without Reg:  No
  • Ans Call Without Reg:  No
  • Register Expires:  3600
  • Use DNS SRV:  Yes
  • DNS SRV Auto Prefix:  Yes
  • User ID:  1777XXXXXXX  (use your CallCentric UserID)
  • Auth ID:  1777XXXXXXX  (use same as UserID)
  • Use Auth ID:  Yes
  • Password:  **********  (use as set in your CallCentric user account - Preferences - Phone Password; SIP Password)  (By default, it's the same as your web login password)

Remember to save all new settings when finished making changes.
Click the Submit All Changes button to SAVE your custom settings.

At this point, you have set all the basic requirements to connect to a VoIP service provider.

Following, are some additional suggestions and reminders:

While the SPA2102 defaults to use G.711u Codec, CallCentric recommends using G.729a to save bandwidth.  If you want the best voice fidelity, I would stick with G.711u.  But, if you do have QOS or data bottlenecking problems, it may be prudent to switch to G.729a to reduce bandwidth requirements of your VoIP calls.

Dial Plans
While the SPA2102 default dial plan will work, you may want to replace the default with the dial plan recommended by CallCentric:


First, completely clear the default plan, then copy and paste this plan in its place.
Save your changes.

There are three reasons to use the CallCentric enhanced dial plan:
  • It accepts *xxx numbers, such as accessing your CallCentric Voice Mail using *123 command
  • It accepts CallCentric Speed Dial numbers such as *75xx (*7500 - *7599).  Your CallCentric user control panel allows you to pre-program 100 predefined speed-dial numbers accessible from your VoIP ATA (i.e. SPA2102).
  • It accepts **275*x. number dialing to allow network peering calls through the Sip Broker network.

Disable Line-2
If you will only be using Line-1 on the SPA2102, I recommend disabling Line-2.  You can always re-enable it in the future if you connect to another account or another VoIP service (like I do).

Disable Provisioning
As the SPA2102-NA is an "Open", "Unlocked", and "User Configurable" VoIP ATA, there is no reason to leave the default Provisioning service enabled.  I recommend setting the "Provision Enable" = NO.
Remember to save any changes.

Before exiting the web administration pages, I recommend that you go back and review all settings and changes just to confirm that all values were entered correctly and saved.

I hope you enjoy using the SPA2102-NA with the CallCentric VoIP service as much as I have.
Happy VoIPing...