From an analog phone

First dial and wait for first person to answer phone

Push the flash button or (push and release hook switch once quickly) on phone and you should hear a dial tone

Dial next number you want to connect with.

Once that person answer push the flash button or (push and release hook switch once quickly)  again to conference lines together

 

To disconnect or remove yourself from call just hang up and the 2 conferenced lines will still be connected.

 

(not sure if this will work)

To add additional lines

                Once you have everyone connected just repeat step 2 thru 4 for each additional people.  Remember you can only connect in one phone line in at a time.

 

Tadiran Telicomm phones

First Dial and wait for first person to answer

push the "Xfer/Conf" button on phone you should hear a dial tone

Dial next number you want to connect 

Once that person answers press the "xfer/conf" button to conference lines together