Busy Lamp Field (BLF)

The Busy Lamp Field, also known as just BLF, are buttons on your IP desk phones that have LED lights built-in to them to provide visual representations of certain VoIP features. It is a very powerful phone system feature that can be used in multiple different ways such as for call pickup, one touch transfers and many more. In this article we will show some of the ways our customers take advantage of this popular feature.

Busy Lamp Field Use Cases

There are many use cases for the Busy Lamp Field (BLF) on Cabertel's phone system, below we will focus on the most popular ones that we frequently configure for our customers.

Busy Indicator

Busy indication, or presence detect as it is sometimes called, is probably the most popular use case for the BLF. We can configure buttons on your phone as BLF buttons that monitor other extensions. For example, in the picture above you can see the Sales button is currently lit red. This means that the phone extension used for sales calls that our phone is monitoring is currently on a call and thus is busy. When they complete that call, the button light will turn green indicating they are now available. Some customers set up multiple buttons on their phones so they can monitor multiple phone extensions. It is a convenient way for managers to see that calls are being answered and staff are busy but also to ensure you do not call a colleague that is already on another call.

Call Pick-up

In addition to detecting whether a colleague is already on a call, you can also see if they have an incoming call and it is not being answered by them. When a call comes in and your BLF button is monitoring that extension, it will change from a solid green color to flashing red. If the person at that extension answers the call it will go red, but if you see it is not being answered you can press that line button on your phone and you will pick-up the call for them and handle it. This can be useful for small businesses where people wear multiple hats at work, for example an administrative assistant may answer sales calls during high call volume times of the day.

Speed Dial

You can also use the BLF buttons as simple speed dial buttons. When you press the BLF button it will call the extension associated with the BLF button.

Call Transfer

Another popular use case for BLF buttons is for quick and easy one-touch call transfers. If you are on a call and need to transfer it to one of the BLF extensions you are monitoring on your phone, first check it is green, thus indicating they are not already on a call, and then press the button and it will call that extension and place the caller on hold. You can now either hang-up and it will bridge the call to that extension, this is known as a blind transfer, or stay on the line and talk to your colleague to pre-empt them on the reason for the call and then hang-up, which is known as an attended transfer. The BLF light will go red during this transfer since their extension is now in the busy state.

Call Parking

Call parking is a very useful feature for some businesses. It can be used in conjunction with a BLF button on your desk phone to show active and inactive call parking slots. For example if you park a call in slot 1 and all of your phones have BLF buttons that monitor the state of parking slot 1, they will change from green to red. If a phone then picks up the call on parking slot 1, the BLF buttons for parking slot 1 will change back to green, indicating that it is free again.

Call Recording

If you have on-demand call recording enabled for your account, we can configure a line button as a BLF call recording button. If you need to record a specific call, simply press the call recording button and it will now flash to indicate it is recording the call.

Any Disadvantages

There are only two things to be aware of when it comes to Busy Lamp Field buttons.

The first is that depending on the IP desk phone you purchased from us, it may not have enough buttons on it to allow BLF functionality. For this reason it is better to consider this feature before purchasing phones so you can buy the right phone for the functionality you require.

The second item to be aware of is data bandwidth. Each BLF button is constantly communicating with our servers in the cloud as it needs to be refreshed frequently as to the state of the phone extensions you are monitoring. For this reason, if you plan to configure multiple buttons for this type of functionality, it adds additional data bandwidth at your work and on our servers. For this reason it is deemed a premium feature and has a small cost associated with it.

Next Steps

If BLF is something that is of interest for your business and you are an existing Cabertel customer, contact your dedicated account manager and they will set it up for you on your phones. This involves us remotely configuring spare line buttons on your desk phone, providing you have some spare. If you are not an existing customer but interested in learning more, use the form below to contact us and we will call you to discuss your business phone service needs.