The Foreign eXchange Station (FXS) port polarity configuration is used to set the polarity of the FXS ports, whether forward or reverse, such that the end-to-end connection between the RJ-11 jack and the router voice-port will be a straight-through connection.
Note: The polarity is set forward in default. If you change the value at the time when the call gets connected or an active call drops, user can hear an audible click sound as the line polarity reverses.
The objective of this document is to explain how to configure FXS ports on SPA100 series phone adapters.
• SPA100 Series
Step 1. In the phone adapter configuration utility, choose Voice > Line 1 / Line 2. The Line page opens.
Step 2. Scroll down to the FXS Port Polarity Configuration area.
Step 3. In the Idle Polarity field, choose the polarity which you want to set before a call is connected from the drop-down menu. The possible values are Forward or Reverse. The default value is Forward.
Step 4. In the Caller Conn Polarity field, choose the polarity which you want to set after an outbound call is connected from the drop-down menu. The possible values are Forward or Reverse. The default value is Forward.
Step 5. In the Callee Conn Polarity field, choose the polarity which you want to set after an inbound call is connected from the drop-down menu. The possible values are Forward or Reverse. The default value is Forward.
Step 6. Click Submit to save the settings.