I have a BBU Plus (the 'white cube' type) for use with my router. This has a 'splitter' type cable to feed the router and future ONT. The end of the cable which goes into the power outlet on the BBU has a yellow barrel connector.
Does anyone know the specification for that connector please in terms of external and centre pin diameters etc?
No doubt someone will give you a more precise answer, but you can use metric drill bits as a gauge for the inner diameter. Outer diameter should be easy enough to judge with a ruler.
I can measure the outside with calipers, but not the inside. Nice idea about metric drill bits. But....how to measure the diameter of the centre pin?
By measuring the hole that it's supposed to fit.
Edit: You don't indicate what it is going to connect to, but for what it's worth, the Smart Hub 2 is a 3.0mm and most ONT's are 2.1mm
You can buy power bricks on Amazon with a number of interchangeable connectors.
So, measure the hole in the barrel connector.
I've tried, but don't have anything accurate enough.
Mr Google's AI tells me that the yellow plug is a 5.5x3.0mm plug, same as the SH2 router used to be. Problem is that the yellow plug is a female socket with NO centre pin which does not appear to be commercially available, only the male equivalent with the centre pin. I sense the need for a fudge....
3.0mm is particularly difficult to get hold of. (It seems to be more an American thing). CPC Farnell seem to be one of the few suppliers of that size in this country. Have a look on their website.