Originally Posted by Airstreamer

We use licensed channels in the 900 mHz band, master/slave 45mHz split, so each site can run full duplex data during the time slot that the SCADA master polls them.

The MDS system is a digital radio where the master has it's carrier in an 'always on' state, (in our system anyway,) and does time division access to each of remote radios. We have them setup 'transparently' so the actual SCADA system doesn't even know that the radio link exists. The actual RTUs "don't speak unless spoken to," so the com data part of the radio channel is idle except for the traffic between the SCADA master and one RTU at a time. However, there is a maintenance channel that is running between the radio master and all the slave remotes full time, but its data is not passed out of the master on the normal data port but shows up on a separate connector. If you hook to that maintenance port of the master, you can get to any radio on the system IF you know its radio address. (There are some discovery tools, but I've not had good luck with them.)

Signal levels, equipment temperatures, programming, etc can be viewed if needed, and if enabled, you can re-configure the radio just as if you had the programming cable plugged directly in. All "over the air" data is encrypted.


We can get 19.2k or even 38.4k if we push it, but mostly we run 9600. They're good for more than 40-50 miles line-of-sight with the right antennas.