Yes, you need to buy at least one U60 or U70 to support any of these channel types.
The SmartServer IoT doesn't come with any built-in FT-10 or power-line network interface. The SmartServer is a multi-port router and you can use one or more U60s/U70 on each SmartServer.
You only need to purchase a U60/U70 if the SmartServer has to have a direct connection to one of the channels below. That is, if you don't use any of the channel types then you don't need to purchase any U60/U70.
For example, If you are only connecting a MODBUS device to a SmartServer then you don't need to buy any U60s/U70s for this SmartServer.
BACnet/FT devices are BACnet devices that also have a LON interface. If these devices are connected to a LON FT-10 channel then you need to purchase a U60.
Product for each channel type:
1. Only one U60 TP-1250 can be used on each SmartServer IoT.
2. When mixing U60 and U70 types on a SmartServer you need to make sure the higher speed channel data that goes between channels doesn't overwhelm the lower speed channel.