Anyone using wt-5
I am not sure about the d4 but the same device is available font the d600 and it requires a mobile app to run on your iPad or smart phone. The app is free and can be downloaded from iTunes.
sorry - I have no information on your other questions.
|High Altitude Rocky Mountain Railroad by cjf2|
from On the Rails...
|Evening at the lake. by Murat ÜNSAL|