Setting up BLF functions on a Linksys SPA-942

With the lastest firmware (v6.1.3), the Linksys SPA-942 can now suppoprt BLF on Asterisk systems. Implementing it is actually quite simple as we will see in this article. If you aren’t familair with BLF, this is called Busy Lamp Field and is used to show the status of another extension and to act as a speeddial key to that extension. While this is very handy with the Linksys SPA-962 combined with the SPA-932 sidecar, its usefullness is somewhat diminshed on the SPA-942 since you only have four line keys and each BLF configuration will use up a line key. This is still quite handy for an assistant to be able to take calls for an executive and know when it is ok to transfer calls. There are plenty of other situation where this is useful and if you find yourself needing this functionality, then it is a real nice feature to have available.


Setting up BLF
From a web browser, go to the IP address of the phone you want to configureand click on the Info tab, if the Software Version is not 6.1.3(a) or higher, you will need to go to the Linksys website and download the firmware for the phone. The update is an executable application under Windows, you enter the IP address of the phone and it will update the firmware for you. If you do not have a Windows-based system, then you will need to put the firmware on a TFTP server and program the phone to go and find the firmware.

Once the phone is on the current version, click on the Admin link on the top of the page, and then click on the Advanced link at the top of the page. Next, click on the Phone tab.

Let’s say we want to setup this phone’s line 4 key to monitor extension 200, we would then go through the following steps:

In the Line Key 4 section, set the options as follows:

Extension: Disabled
Short Name: 200 (or to any text you want)
Share Call Appearance: Shared
Extended Function: fnc=blf+sd;sub=200@$PROXY;ext=200@$PROXY

In the Extended Function field, note that the extension we are monitoring is listed in two areas.

In the next section (Line Key Extended Function section) you need to change the Server Type to Asterisk.

Finally, go to the bottom of the page and click on the Submit All Changes button. The phone will reboot and the display will now show a different icon for the fourth line. If you press the line four key, it will dial the extension you setup. If the extension you are monitoring is on a call, the line key will turn red. That’sd all there is to it.