VoIP Cookbook: Connect PSTN using Linksys SPA9000 and Linksys SPA400
Connecting PBX softswitch like Linksys SPA9000 to the PSTN can be carried out in several ways. One of them is to use the Linksys SPA400 as mediator to PSTN. What you have to do is to make SPA400's IP address to be fixed, enable User ID to register itself to SPA400, enable SPA9000 to register itself to SPA400, and enable SPA9000 to use SPA400's trunk for PSTN calls. SPA400 configuration can be done through the web, using the given default username without a password.
Through the Setup menu, click Basic Setup. Here we have configure fixed IP address, IP subnet mask, and gateway IP address, information on Domain Name Server (DNS) Address and NTP. For our example, we use 202.134.2.5, 202.46.3.178, and time.nist.gov for Primary DNS, Secondary DNS and NTP Server, respectively.
Through the Setup menu, click SPA9000 Interface. The configuration you have to do is as the following:
Create an account on SPA400 such that SPA9000 softswitch can register.
- Create an account in SPA400 so a softswitch like SPA9000 can be registered.
- Configure SPA400 so it will know the IP address and port of the softswitch/SPA9000. It is recommended that you choose “Discover Automatically”
On the Setup menu, click Voice. Here we can configure the sort of codec we want to use and other setting parameters such as Wait-for-Answer time.
On the Setup menu, click Voice. In the Line Settings tab, you can configure the transmit gain, receive gain, impedance, ring voltage, on-hook speed, etc.. Basically, we do not need to change these values of these parameters, and simply use the default values.
Through the Setup menu, click the Voicemail Server tab. Here we can set some important parameters of the Voicemail server, such as:
- Server Port – default 5090
- SPA9000 User ID – user ID for the SIP Proxy to register to Linksys SPA400
- SPA9000 subscriber ID – subscriber ID for the SIP Proxy to obtain Voicemail
- Mailbox Deposit Number – the number needed to put voicemail. The default value is 900.
- Mailbox manage number – the number used to manage Voicemail. The default value is 800.
One of many great things about SPA400 is its capability to store Voicemail data in USB storage. Through the Setup menu and Voicemail Users, we configure the user and password of our Voicemail. By clicking on the “enable” box of any user, we can now activate that user account.
Go to Administration, then click Management. Here we can configure our username and password from Gateway Administrator. The default username is “Admin”, without a password.
Through the status menu, you will find more information on SPA400 operation, such as, time, IP address, subnet, gateway, DNS, USB disk etc. The most important parameter is the SIP Registration Status. It indicates the condition of the SIP Proxy we use: whether SPA9000 or Asterisk is successfully registered with SPA400 or not. If the SIP Proxy is successfully registered with SPA400, you can use SPA400 as an Analog Telephony Adapter to call to Telkom.
While you are still in status pane, notice that there is also the status for Battery Level. This shows the voltage available at RJ-11 port of SPA400. If it is connected to your PSTN provider, then the voltage normally is about 45 V. If it is connected to PABX, the voltage experienced by the RJ-11 port is around 24 V. If all ports have their voltage level 0 V, then SPA400, when we attempt to place a call, will get a busy signal.