To add a RTSP stream from a NVR to a decoder (SPD-150 or SPD-151), use the following RTSP string format:
rtsp://<NVR_IP>:558/LiveChannel/<ch_no>/media.smp/session=1
Where 558 is the RTSP port on the NVR (this is the last port n the Device Port list)
Using the standard RTSP string for NVRs is not recommended as the decoder logs in and out of the NVR repeatedly and this causes issues accessing the stream.