Most standard BACnet devices can support up to 32 devices on a single trunk line without a repeater. I was not able to find a limit for the T3 modules Temco offers in the documentation provided. I would assume that the limit for these is also 32. Is that correct?
That’s a good rule of thumb mainly to keep the network cable easy to troubleshoot and maintain. In theory the RS485 driver chips will support up to 255 devices but it will be a nightmare to commission the cable. Also the network will be faster and more responsive if you limit your systems to about 32 devices.