Friday, 1 January 2010

Configuring PAP2T VoIP ATA with CallCentric

The focus of this article is to illustrate how to configure the Cisco Linksys PAP2T-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 PAP2T-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 PAP2T-NA Firmware Version = 5.1.6 and Hardware Version 0.1.5
I'm also using the PAP2T behind my Linksys WRT54G NAT-Router.

I will be following these basic steps:
  1. Reset PAP2T to Factory Defaults using its IVR interface
  2. Login to the PAP2T web-based configuration interface
  3. Configure Line-1:  VoIP Proxy, User ID, Password, etc.

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 PAP2T 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 ready state.

  1. To activate the PAP2T 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.

Connect and Login to the PAP2T Web Based Configuration Interface
Connect to the PAP2T using its DHCP assigned IP address, assigned by your router.  In my case, I'm using the WRT-54G as my LAN NAT-Router.  My PC is connected to port-1 and the PAP2T is connected to port-2 of the router.

Typically, you will determine the IP address assigned to the PAP2T by  using its IVR system:
  1. To activate the PAP2T IVR, lift the connected phone handset and press the Star key four (4) times (* * * *).
  2. After the IVR voice prompt, enter the Check IP Address code:  110, followed by the # key (110#).
  3. Write down or remember this IP address.
  4. Hang-up to end IVR.
  5. Connect to the PAP2T by entering its assigned IP address, using your Web Browser
    (In my case, I'm using Google Chrome browser)
  6. By default, you will be viewing the PAP2T "Info" page, in "Basic" view.  By default, there is no password required to connect and login.

Configure Line-1:   VoIP Proxy, User ID, Password, etc...
To begin configuration of the PAP2T, you need to switch to "Admin" and "Advanced" view.
By default, the PAP2T does not require an admin password.


Click on Line 1 to go to Line 1 configuration page:


The Line-1 page is where you will be configuring VoIP service for your primary line 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 required by CallCentric:
  • NAT Mapping Enable:  No
  • Nat Keep Alive Enable:  No
  • Proxy:  callcentric.com
  • Use Outbound Proxy:  Yes
  • Outbound Proxy:  callcentric.com
  • 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 assigned UserID)
  • Auth ID:  1777XXXXXXX  (use same as UserID)
  • Use Auth ID:  Yes
  • Password:  **********  (use PW as set in your CallCentric user account Preferences page)
    (by default, SIP PW is the same as your CallCentric web account login, but can be changed in Preferences)

Remember to "Save Settings" when finished making changes.
At this point, you have set all the basic requirements to connect to a VoIP service provider.

Following, are some additional suggestions and reminders:
Codecs
While the PAP2T 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 PAP2T default dial plan will work, you may want to replace the default with the dial plan recommended by CallCentric:
(*xx.|*xxx|*75xx|[3469]11|0|00|1xxx[2-9]xxxxxxS0|xxxxxxxxxxxx.|**275*x.)
Just copy and paste this plan over the default plan.

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. PAP2T).
  • 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 PAP2T, 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 PAP2T-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.


Allow VoIP to Pass Through Firewalls
Remember, the PAP2T is designed to function behind a router and firewall.  For VoIP behind NAT-Routers to function "reliably", you need to Port Forward or Port Trigger the required VoIP SIP and RTP ports that carry the VoIP traffic.

Note:
If you use "port forwarding" (vs. port triggering) through your router, this usually requires forwarding to a fixed IP address.  Thus, you would need to fix the IP address of the PAP2T to a static value, and then set port forwarding address in the router to match the static IP address of the PAP2T.

Initially, I recommend that you try using Port Triggering of SIP and RTP ports through your router and leave your PAP2T in DHCP mode.  If triggering isn't working for you, then resort to Port Forwarding SIP/RTP ports to a fixed IP address on the PAP2T.

Enjoy your VoIP calls from your PAP2T-NA configurable ATA.