Support for Arris NVG448BQ

Can anyone tell me how we can do the serial connection of ssh to the Arris NVG448BQ modem/router/wifi?

I see at least two 4 pin headers on the photos at

There's also Adding support for Arris NVG443B? - #3 by slh

Screenshot 2023-05-08 231850

Am I right?

Trial and error, and perhaps a volt meter.