Do I need an ATA?

Hello @Chris_Grantham

Welcome to the forum.

Looking at https://spdl.zyxel.com/EX5601-T0/quick_start_guide/EX5601-T0_001.pdf and https://www.zyxel.com/service-provider/global/en/products/ethernet-cpe/ethernet-iads/ex5601ex5600-t-series It seems like it has an ATA in built in.

Depending on where you live and the plug on your PSTN phone, you might need a converter to an RJ11 plug.

For example, https://www.amazon.co.uk/Rhinocables%C2%AE-Socket-Telephone-Adaptor-White/dp/B00EVS5UZ2/ref=asc_df_B00EVS5UZ2?mcid=75a172d6a9eb378a9cd87c5f3e26a973&tag=googshopuk-21&linkCode=df0&hvadid=697342549349&hvpos=&hvnetw=g&hvrand=2125735404116547765&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9045065&hvtargid=pla-564720359273&psc=1&gad_source=1 for the Rhino BT socket to RJ11 plug adapter.

Kind regards,

Tony