GDX5 Video telephone

[ScottP]

Hi all, just bought a 9 year old property with a GDX5 video telephone, it works but there is no video, and the handset is very quiet, while the ringer would wake the dead. People can hear me, but I can hardly hear them at all. And we jump out of our skin when it rings. Can anyone help with what the rotary controls on the side do, i.e. which is which as they aren't marked, and any ideas why the video is dead?

 

[ScottP]

Bump

 

[sparkymarka]

Don’t think anybody on here installs them !

 

[ScottP]

Thanks for replying. I saw another thread in here about the same unit so I posted hoping someone would know. It's like joining MI6 finding tech details on this door entry phone.