Get machine data - Fanuc 0-T

Good morning everyone,
my name is Flavio, I'm an Italian guy. I've developed a monitoring production software with my colleague. We use to connect it with new machine, we have a FOCAS connector that gets data from fanuc CNCs, and other protocols. We are now facing a new project: we are connecting old machines, without ethernet, so no FOCAS. We use electrical contacts to get information ,for example green semaphore -> working status, red semaphore -> alarm. We can connect and get data from almost of them, but a couple of machine doesn't have semaphore.
Do you have a better idea to get data from old machines? a guy told me that fanuc has a M4 connector but I can0t understand what it means....
Thanks everyone and sorry my english.
Have a nice day, Flavio

I have been personally involved in getting information from older (legacy) Fanuc controls for 10 years.
Send me an PM to discuss it.