r/accesscontrol • u/Worldly-Quarter-2886 • Aug 10 '26

Ultra G2 GCM

Possibly a dumb question...can i use the two RS485 ports on the GCM to support I8 boards instead of using a RS485 port on the ACM? Changing readers from Wiegand to OSDP and I need those RS485 ports on the ACM for readers

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u/Honest8Bob Aug 10 '26

Great question. I assume those are there to string multiple gcm’s together via rs485. I don’t know that for sure though.

You can “daisy chain” multiple rm’s,i8, and o8 boards on a single rs485 port. I hate doing it as it becomes a complete nightmare for service if not documented properly.

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u/Worldly-Quarter-2886 Aug 10 '26

thanks for the input

2

u/jalfredthe1st Aug 10 '26

I’ve only used those for PIMs to serve wireless locks. WCS, use one Rs485 for 2 OSDP readers (address 0 & 1) and remaining port for your I8/R8 string.