Effective 1 January 2004, the MD9 Multidrop Interface was generally replaced for new multidrop applications by the MD485 Multidrop Interface. However, the MD9 remains available for customers with existing MD9 networks.
The MD9 Multidrop Interface links a computer to as many as 200 dataloggers over a single coaxial cable. Each datalogger in the network is connected to an MD9 that has a unique, user-assigned address. Communication between the computer and a specific datalogger is routed through the MD9’s address allowing the rest of the network to remain in quiescent mode. Total coaxial cable length can be up to three miles; each MD9 in the network slightly reduces the maximum transmission distance.