Preface
Fair Dinkum!

Chapter 1
I have the NBN as HFC* (ISP Optus, to be complete) with one cordless Dect 6 phone base station (with 2 handsets)
connected to the modem. See image below for details.

Now, of course, all the old phone extension outlets do not work, but I have a spare Dect 6 base station (with 1 handset)
that I would like to press into service. Ie, have two different (brand) base stations on the desk and both using the same
phone service.

At first I thought it would just plug into the 2nd phone port on the modem, but that only gives an "engaged" tone. So I'm
asking if anyone has come up with a solution to this problem.

Ta in advance. (Boy! - Talk of progress - 21st Century, NBN, and Foxed by some simple telephony.)

* HFC - Hybrid Fibre Cable

Details of setup...
DSC_5028aclr.jpg