You would need to follow the instructions for an ANALOG phone. The Conf feature of the VTX 1000 is just a place where you can program a Vertical Service Code or Feature code when required on a systems (e.g. Mitel sx2000 multi-party conference.
For the Meridian you just need the flash key.
To add a new party to an established call on an analog (500/2500 type)
telephone, follow these steps:
1 Flash the switchhook.
You hear three beeps followed by dial tone. The first party is on hold.
2 Dial the telephone number of the person to be included in your call.
When the call is answered, you may talk privately with the new party.
3 Flash the switchhook to include all parties in the call.
4 To add more parties to the conference (up to six, including yourself),
repeat steps 1-3.
Note: If you make a mistake while dialing or receive a busy signal, flash
the switchhook to return to the original call
KE407122
When I find myself on the road less travelled, it just means I'm lost.