Access MD3200 Service Interface via Putty

Hi All, I recently acquired a MD3200 and I cant work out what the controller IP addresses are.

After a bit of hunting around, I found some instructions on how to connect to it via COM port.

However, when I press CTRL BREAK I get:

Press within 5 seconds: <S> for Service Interface, <BREAK> for baud rate

If I press S or caps S nothing happens.

If I press BREAK then I get the baud rate settings, so something is happening.... but I cant get into the Service interface...

Is there something I am missing?

Thanks,

Nathan