Yes it is, subject to software version etc.

What version handsets do you have ? Mark I has DOT at the 9 o'clock position on the centre dial and Mark II has the word INT

Assuming you have a Mark II Beocom 6000 you can have a conference call as follows:-

During an external call, you can call another handset in your system to establish a conference call. If one participant hangs up, the call continues with those handsets remaining on the call.

Whilst you are connected to your external caller press INT then turn the dial for the handset you wish to join the call then press the PHONE key and when the internal phone is answered turn the dial until you see CONFERENCE? and then press OK (centre of dial)

Two internal phones and the external caller are now connected to the same line and can speak and hear each other.

There is a little known facility on the Mark II Beocom 6000's named "Call break in".

You can establish an internal conference call  by "breaking in" on a call in progress, however this should only possible if you use a handset with the Beoline base. I have never tried the "break in" facility with an analogue phone on the same line, but you could try it.

To use the "Call break in" facility, first establish a call using your from your Beocom 2500, then on your Beocom 6000 it should show on the display "Line is Busy", then press the HANDSET key on the Beocom 6000 followed by OK (centre button of the dial) and you have broken into the call. Well, you have for certain if you have a Beoline with Beocom 6000 and/or Beocom 2, I would be interested to note if it works with an analogue phone..

Christian,

You would be correct, if both phones were analogue, but we have here one analogue and one Beoline (DECT) and he wishes to join the call from the Beocom 6000 not the Beocom 2500.

Christian is actually right - there is no problem if there is only 1 DECT phone inwolved. If I pick up the call with my beocom 2500 I can join the call on my beocom6000 by just pressing the "phone" button.

My handset are mark I - with the DOT button