I had my medical for groundstaff a couple of days ago. It consisted of filling in quite a bit of paperwork detailing your medical history.
Vision - near and fields of vision, colour
blood pressure, pulse
mobility and balance, ie moving your arms and clapping, lifting your legs and turning them , crossing your arms, closing your eyes while nurse counts to 15
vision - distance
hearing
breath - normal and peak flow, taking a deep breath and blowing out for as long and then as hard as you can.
urine sample for drugs and alcohol, also breathe into a breathalyser.
I assume a signallers medical would be broadly similar.
I was told I was slightly overweight but that it wasn't a problem, the nurse asked if I was doing anything to lose weight and I said I hoped a more physical job would help me in that regard.