Question Unusual Headphone socket Q

[TerryFR]

Can anyone tell me what this headphone socket on the back of Hitachi TV? It's marked 3.8V 1A and is smaller dia. than standard 3.5mm. There's a headphone symbol marked around the socket.

 

[helpstar]

Which Hitachi TV model is it?

 

[hang-the-9]

Can anyone tell me what this headphone socket on the back of Hitachi TV? It's marked 3.8V 1A and is smaller dia. than standard 3.5mm. There's a headphone symbol marked around the socket.

Maybe for a hearing aid interface. Only a few audio jacks out there that are smaller than the 3.5mm jack, there is a balanced connection (which I have never seen in a TV) or maybe a socket to attach a specialized hearing aid device. Would help if you listed the exact model maybe with a link to it and a picture of the jack.