The DSR505 is listed at hifi-remote.com, and also at Sling Community.
It appears that it does work with Cable 0869.
However, the DSR505 can be setup with various Unit numbers, and 0869 is specifically configured for Unit 0.
Please check if you can configure the DSR505 for Unit 0, or if that isn't practical (because you have another DSR that conflicts, e.g.) we can show you how to enter EFCs so that the remote send some other unit number.