Support for ISCO pumps without Ethernet

[MarkRivers]

Some ISCO pumps do not have Ethernet so they cannot use Modbus TCP.

We could add support for using RS-232 commands. Max Wyman has started on this. But I wonder if that is worth the effort to support well.

Do pumps without Ethernet support RS-485 with Modbus-RTU? Mine does, using on the same connector as RS-232. If they do then I think that using Modbus RTU is preferred, since the existing databases and medm screens can be used. It might require purchasing an RS-485 terminal server, but those are not very expensive.