No, the Polycom Manual

https://support.polycom.com/global/...oundstation2_with_display_user_guide.pdf

Plus this from what we call an SLT manual for the ATA for an CICS or MICS.

Note your labelling is apparently link, instead of Recall.

Conference

The Conference feature lets you establish a conference call between yourself
and two other parties.
1. Make or answer the first call.
2. Press Recall 2 to put the call on hold.
3. Make the second call.
4. Press Recall *3 to establish the conference.
If the second person you call is busy, or if there is no answer:
1. Hang up the handset.
2. Lift the handset again.
3. Press Recall 2 to return to the first call.
To place the conference on hold:
1. Press Recall 2.
The other two parties in the conference remain connected.
To rejoin a held conference:
1. Press Recall 2.
To split a conference into two separate calls:
1. Press Recall #3.
To alternate between the two separate calls:
1. Press Recall 2.
To reconnect the conference:
1. Press Recall *3.
To disconnect one party:
1. Press Recall #3 to put the one of the parties on hold.
2. If you are not connected to the party that you want to disconnect, press
Recall 2.
3. Hang up the handset.
4. Lift the handset again.
5. Press Recall 2.

You are reconnected to the call on hold.


FWIW, I've never worked on an Option.