negative only connected between panel and power rios.

Neg common isn't needed for rs485.

Neg common isn't needed for rs485.

 

It is on Galaxys

It isn't mate.

Try it

I only commoned em when using split outputs

All modules are at 100% in Diagnostics except Keypad 19 which is at 0%.

I have seen the ethernet comm port 4 and the Keypad 15 both drop to 96% occasionally

but the ethernet card is in the panel connected using the engineer lead that plugs on to the four pins

All modules are at 100% in Diagnostics except Keypad 19 which is at 0%.

I have seen the ethernet comm port 4 and the Keypad 15 both drop to 96% occasionally

but the ethernet card is in the panel connected using the engineer lead that plugs on to the four pins

 

And then you data line out is taken from the ethernet module ?

It isn't mate.

Try it

I only commoned em when using split outputs

 

Must be, as it doesnt work on remote buildings unless common the negs, may be as they are not on the same supply.

Honeywell documents the ground going through, so that's all coblers?

Shouldn't make any odds 485 doesn't need a voltage reference. It's common advice due to output switching really not needed. It's not done on cameras across phases for instance.

Is it an adt firmware

Honeywell documents the ground going through, so that's all coblers?

Look at the 485 protocol it will show it's needed. Plus as above you link negs on cameras. Trust me 485 does not need a common to work. Other stuff does but not the data

Is it an adt firmware

Firmware is irrelevant

Don't get me wrong its good advice to prevent switching issues, but isn't needed for just data

I wouldn't as a rule common negs unless switching outputs across expanders. Electrical isolation is preferable imo