Enable BLF in 3CX Phone

[jeremy]

I'm trying to get BLF (Busy Lamp Field) working in 3CX.

I can add BLF monitors to the "Soft Keys" area, but they always show in gray instead of indicating the status of the monitored extension.

We are using a GrandStream UCM6108 PBX. Their instructions for BLF say that you need to make an Event List in the PBX, and then enter the URI of the event list into the phone for it to subscribe. But I don't see anywhere to enter an Event List URI in 3CX Phone. Is this why BLF is not working? Or is there a different way to get it to work?

The extensions I wish to monitor are also using 3CX Phone.

 

[leejor]

Just to be clear...are you using the 3CX Phone (version?), in conjunction with a GrandStream UCM6108 PBX, and not the 3CX PBX?

If that is the case, then there may be some incompatibility issues.

 

[jeremy]

Thanks for the reply.

Yes, we use a hardware PBX appliance because we have both PTSN lines and VoIP trunks. We're using 3CX Phone 6 for Windows as the phone.

I had thought that BLF was more standardized, so I didn't realize that there could be compatibility issues. In what way does 3CX's BLF differ from other implementations? Perhaps I should also take this up with Grandstream?

 

[leejor]

Even though 3CX Phone version 6, works with other VoIP providers, it was probably never intended to be used with other PBX's to provide more "advanced " features. Grandstream may have their own way of implementing BLF that, while working with their sets, may not be SIP standard, or at least, not compatible with the BLF feature as implemented on the 3CX Phone.

I suppose, if you had the time, you could use something like Wireshark (and a 3CX PBX installation) and compare how 3CX and Grandstream differ in their messaging. Still won't solve your problem.

 

[craigreilly]

You mention you use a hardware pbx appliance because of the need for pstn and VoIP lines. 3cx has that capability as well...

 

[jeremy]

I know that it's true that 3CX can use PTSN lines. And we have FXO cards as well from when we used to use plain old Asterisk.

But at some point we got sick of mucking with Asterisk, and that was before 3CX was around. So we bought the GrandStream PBX and it served us for many years. When it died, they gave us a deep discount on the new unit. So it was kind of a no-brainer to go that route.

It was only recently that most of our staff ditched their hardware (Grandstream) phones in favor of 3CX's softphone (the best SIP softphone for Windows that we could find) so that they could more easily use commodity USB or Bluetooth headsets.

I don't doubt that 3CX has an array of value-add features over Asterisk or Asterisk appliances. But due to our investment we are most likely going to be stuck with the Grandstream unit for a while. I tried to sign up for their forums in order to ask there about BLF, but I never got the activation e-mail, even in my Spam folder. So.... yeah. Next time we need a new PBX we'll probably use 3CX, if only because all of us use the softphone (which was probably your ploy in making an excellent free softphone... mission accomplished!)

 

[leejor]

I suppose that you realize that the version of the 3CX Phone (6) that you are using is pretty much obsolete. It would not surprise me if it disappears, at some point, from the downloads.

The newer versions (11 & 12) have been specifically designed to work with the corresponding versions of the PBX, and no longer, with any other VoIP system/Provider.

They do, however, and add many additional features that may make the "switch" worth considering.