Adding a PLAR (automatic ring down) to Cisco SIP Phone with SideCar (Key Expansion Module)


For those of us that work in the financial sector with trading floors, it is common to find expensive turrets spread across trader’s desks. Traders love their turrets and features that come with them, especially the ability to have hundreds of PLAR or ringdown lines, dual handsets, and a bunch of other features. Sometimes a turret isn’t necessary, the features are overkill and/or there isn’t a way to justify the cost of a $3000-$6000 unit.

In most cases the turret is used to terminate broker lines and this is what traders typically use them for. PLARS can be terminated on a cisco phone if you already have them configured in Call Manager.

My previous article found here provides information on how to set up the PLARS in Cisco Call Manager

For this article we used a Cisco 8961 SIP Phone with a Key Expansion Module.

Adding a ringdown to a phone is simple enough by simply assigning the Directory Number to a button. Make sure you select the correct Route Partition and Calling Search Space. The problem we encountered was the ringdown(s) didn’t work whenever we hit the respective button. So you’re wondering what we did?

We created a SIP Dial Rule and selected ‘7940_7960_OTHER’

For the Dial Rule that we created, the first 5 lines are mapped to the 5 buttons on the 8961 phone, so you have to configure those lines to match whatever you have them set up for. For example the first three lines on our phones are set up with the users directory number. The other 2 are either not used or used when needed. Our directory numbers are 4 digits and start with ’16’ So the configuration looks like the following:

SIP Dial Rule

Now moving on to the Key Expansion Module. Depending on what buttons you want to assign, your SIP Dial Rule will have to be set up to match. In our case we used the next available lines in order 6, 7, 8, 9.

SIP Dial Rule PLAR

Now that you have the SIP Dial rule configured you should be able to hit the button and ring out to the distant end.

A couple of things to note. We are using a different directory number for voicemail so a button had to be programmed for that. We also found that if you don’t have ‘Always Use Prime Line’ set to ‘true’ a user can mistakenly go off hook on a  ringdown. Lets say for example they were tying to make a regular phone call, if the button that is selected on your phone (highlighted blue on the 8961) is a ringdown line, as soon as you pick up the handset it will ring the distant end so make sure to tell your users to select their own personal line before attempting to make a phone call.