I don't see why not. Even if you don't use SDS it won't hurt to have it available.
Besides, many people here believe that SDS is simply a matter of coding, not hardware. As long as you have your microphone connected to the MIC IN pins on the RNS-E, your hardware will be all set.
To use SDS with a TEL interface:
The RNS-E also has a microphone pass-through to the TEL interface, so you'd need to connect the RNS-E "MIC OUT" pins to the TEL interface "MIC IN" pins.
Besides, many people here believe that SDS is simply a matter of coding, not hardware. As long as you have your microphone connected to the MIC IN pins on the RNS-E, your hardware will be all set.
To use SDS with a TEL interface:
The RNS-E also has a microphone pass-through to the TEL interface, so you'd need to connect the RNS-E "MIC OUT" pins to the TEL interface "MIC IN" pins.